Rear axle fluid change - tips? - questions
08-17-2006, 10:17 AM
#1
Melting Slicks
Thread Starter
Rear axle fluid change - tips? - questions
DIY with pics on how to change the rear axle oil, plus other axle info:
http://forums.corvetteforum.com/show....php?t=1497063
---------------------------------
I decided to swap the oil in my rear axle in hopes of at least temporarily getting rid of the clutch plate chatter when cold.
I checked the forum FAQ and did not see any DIY or tip threads regarding a rear-end fluid change. Or did I miss it? If so, please direct me to it. If one does not exist, perhaps we can create one here.
I realize that this is a very simple procedure, but I figured I'd collect any extra info / tips before jacking the car up. Sometimes that one extra little tip can save time and/or a certain degree of aggravation.
So far, per checking the 2006 owner's manual and 2006 shop manual:
For base C6:
Requires 1.69 quarts of SAE 75W-90 Synthetic Axle Lubricant, GM part# U.S 12378261
Also requires 4 ounces of Limited Slip Axle Lubricant Additive, GM part# U.S. 1052358
Fill and drain plugs should be torqued to: 35 Nm or 26 lb/ft.
Questions:
1. What type of socket is needed for the fill and drain plugs? Allen or torxs, or? What size?
2. Is it better to raise vehicle with rear wheels hanging (car on jack stands) or rear wheels on a surface (rear wheels on ramps)? I'd think it would be better to have the wheels hanging so that the axle is lower and more accessible, however on some cars this is not necessarily the case due to other interference.
3. What is the recommended method for getting the oil into the fill hole? Seems that there may not be room to hold the lubricant bottle above the hole. Is there a recommended pump tool, or? In the old days when filling manual trannies I'd just connect a hose to the end of the lube bottle and squeeze the bottle, forcing the lube up the hose and into the trany... but often this got messy, oil would eventually leak out of the hose connection, etc. Is there a better way?
4. Why not mix the oil and additive together BEFORE adding it to the axle? The TSB says to drive figure 8s after the fill to mix the fluids, but it would make more sense to me to just mix 4 ounces of additive evenly to the 1.69 quarts of oil first, then add to the axle. Any good reason NOT to do this? Or just a waste of time? One concern is that I'd have to drive quite a few miles from my garage to get to a place where I can safely and legally do ten figure 8s.
5. Does the axle really take 1.69 quarts of oil plus 4 ounces or additive? Or does it take more... or less? I know from experience that for whatever reason, the published capacity specs for trannies and rears are not always accurate.
6. Does any part of the car need to be disassembled to gain adequate access to the fill plug? Such is not mentioned in the shop manual, but figured I'd ask just in case. Wouldn't be the first time a manual forget to mention an important step.
7. Any other tips, tricks, etc?
Again, don't mean to make a big deal out of an extremely basic procedure, but it helps to be armed with as much info as possible before doing a procedure on a specific car for the first time.
Thanks!
http://forums.corvetteforum.com/show....php?t=1497063
---------------------------------
I decided to swap the oil in my rear axle in hopes of at least temporarily getting rid of the clutch plate chatter when cold.
I checked the forum FAQ and did not see any DIY or tip threads regarding a rear-end fluid change. Or did I miss it? If so, please direct me to it. If one does not exist, perhaps we can create one here.
I realize that this is a very simple procedure, but I figured I'd collect any extra info / tips before jacking the car up. Sometimes that one extra little tip can save time and/or a certain degree of aggravation.
So far, per checking the 2006 owner's manual and 2006 shop manual:
For base C6:
Requires 1.69 quarts of SAE 75W-90 Synthetic Axle Lubricant, GM part# U.S 12378261
Also requires 4 ounces of Limited Slip Axle Lubricant Additive, GM part# U.S. 1052358
Fill and drain plugs should be torqued to: 35 Nm or 26 lb/ft.
Questions:
1. What type of socket is needed for the fill and drain plugs? Allen or torxs, or? What size?
2. Is it better to raise vehicle with rear wheels hanging (car on jack stands) or rear wheels on a surface (rear wheels on ramps)? I'd think it would be better to have the wheels hanging so that the axle is lower and more accessible, however on some cars this is not necessarily the case due to other interference.
3. What is the recommended method for getting the oil into the fill hole? Seems that there may not be room to hold the lubricant bottle above the hole. Is there a recommended pump tool, or? In the old days when filling manual trannies I'd just connect a hose to the end of the lube bottle and squeeze the bottle, forcing the lube up the hose and into the trany... but often this got messy, oil would eventually leak out of the hose connection, etc. Is there a better way?
4. Why not mix the oil and additive together BEFORE adding it to the axle? The TSB says to drive figure 8s after the fill to mix the fluids, but it would make more sense to me to just mix 4 ounces of additive evenly to the 1.69 quarts of oil first, then add to the axle. Any good reason NOT to do this? Or just a waste of time? One concern is that I'd have to drive quite a few miles from my garage to get to a place where I can safely and legally do ten figure 8s.
5. Does the axle really take 1.69 quarts of oil plus 4 ounces or additive? Or does it take more... or less? I know from experience that for whatever reason, the published capacity specs for trannies and rears are not always accurate.
6. Does any part of the car need to be disassembled to gain adequate access to the fill plug? Such is not mentioned in the shop manual, but figured I'd ask just in case. Wouldn't be the first time a manual forget to mention an important step.
7. Any other tips, tricks, etc?
Again, don't mean to make a big deal out of an extremely basic procedure, but it helps to be armed with as much info as possible before doing a procedure on a specific car for the first time.
Thanks!
Last edited by Vet; 09-23-2006 at 03:52 PM.
08-17-2006, 10:44 AM
#2
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be sure to remove the filler plug first. It would not be good to drain it and then find out you can't get the filler plug out. Also, I think the TSB says to fill with non synthetic fluid and only use the synthetic if the plates have been replaced. If you look at the TSB it shows using a part number that is different from the synthetic part number. Otherwise, a real easy fix. 
08-17-2006, 11:04 AM
#3
Good questions - I hope these answers help. It certainly makes sense to be prepared!
One thing I'll mention up front - although its called a transaxle, its really a transmission and differential bolted together. They use separate and different lubricants (transmission uses ATF). As long as you're mainly concerned with the differential clutch chatter you needn't worry about the transmission, but I'll throw in the info on that too. Some folks have found better shifting by changing to Royal Purple Syncromax, and you'll be under there anyway.
1. What type of socket is needed for the fill and drain plugs? Allen or torxs, or? What size?
It's a 10mm hex (Allen) type. You'll want a ball-end driver, either a Bondhus L-type or a short (less than 2 inch shaft) socket type (Snap-On works). Some of the socket type have fairly long (about 4 inch) shafts and won't fit.
The transmission uses a 3/8 inch square drive. Easy to get to.
2. Is it better to raise vehicle with rear wheels hanging (car on jack stands) or rear wheels on a surface (rear wheels on ramps)? I'd think it would be better to have the wheels hanging so that the axle is lower and more accessible, however on some cars this is not necessarily the case due to other interference.
The axle doesn't hang; it stays in place (IRS). Raise the vehicle so that it is approximately level or the front is slightly higher than the rear (the drain hole is at the back). Four jack stands work well, or drive the front onto ramps and then jack up the back.
If you jack up the front you'll need a low-profile "racing" jack; many won't fit under there. Jack under the crossmembers using a piece of wood or something to prevent scratching and spread the load over 2 or more ribs. Ditto for the rear, although you've got a little more room there.
Place jackstands under the crossmembers, again spanning two or more ribs. Some jackstands have v-shaped notches; these don't work well. Find the sort with a fairly flat saddle on top, or modify the V-shaped ones to a saddle.
An alternate jackstand location is under the frame, with jacking pads placed in the tie-down holes. Again, you'll want a jackstand that will firmly support the pads.
3. What is the recommended method for getting the oil into the fill hole? Seems that there may not be room to hold the lubricant bottle above the hole. Is there a recommended pump tool, or? In the old days when filling manual trannies I'd just connect a hose to the end of the lube bottle and squeeze the bottle, forcing the lube up the hose and into the trany... but often this got messy, oil would eventually leak out of the hose connection, etc. Is there a better way?
Put a 1 to 2 foot length of 1/4 inch plastic tubing on the nozzle of the bottle, with the other end in the fill hole. Then hold the bottle up between the mufflers and squeeze.
If you want to do the transmission too, a fluid pump that screws into the bottle ($5 at most auto parts stores) is the way to go. Again a plastic tube is required.
You can try the fluid pump for the diff lube, but its pretty thick to pump that way. The squeeze method worked well for me with little mess.
4. Why not mix the oil and additive together BEFORE adding it to the axle? The TSB says to drive figure 8s after the fill to mix the fluids, but it would make more sense to me to just mix 4 ounces of additive evenly to the 1.69 quarts of oil first, then add to the axle. Any good reason NOT to do this? Or just a waste of time? One concern is that I'd have to drive quite a few miles from my garage to get to a place where I can safely and legally do ten figure 8s.
I'd pre-mix it in the first bottle, not the second, so that its all delivered even if the 1.69 quarts is a little off. The figure 8s are not really to mix the fluids, they're to work the new fluid and additive in between the clutche plates. I don't think theres a problem with driving a ways to get to a figure 8 friendly zone; you've still got the old lube between the plates.
Most of the synthetic lubes (Mobil 1, Red Line, Royal Purple) say you don't need the additive, or to use it only if required. But as far as I know the only downside to using it would be slightly decreased limited-slip performance, and if you want to be sure you don't chatter that's probably the way to go.
I've got Mobil 1 75W-90 gear lube in mine, never had a chatter.
5. Does the axle really take 1.69 quarts of oil plus 4 ounces or additive? Or does it take more... or less? I know from experience that for whatever reason, the published capacity specs for trannies and rears are not always accurate.
It takes less than 2 quarts, I probably have about 1/3 of a bottle left. In any case, 2 quarts is plenty to account for minor spillage.
6. Does any part of the car need to be disassembled to gain adequate access to the fill plug? Such is not mentioned in the shop manual, but figured I'd ask just in case. Wouldn't be the first time a manual forget to mention an important step.
No, as long as you have the right tool to get the plugs out and some patience to work it into place. Let the car cool enough so that the mufflers aren't hot before starting, you'll be working around them a lot.
7. Any other tips, tricks, etc?
Once you've got the car raised, give it a couple good shoves to make sure its stable. You'd rather have the car repaired than have it fall on you - there really isn't much room under there!
Remove or loosen the fill plug before removing the drian plug. That way if you can't get the fill plug out you still have the old fluid in there!
If you're using the Bondhus L-shaped ball-end Allen wrench (about $12 a set) use the long (ball) end to remove the fill plug, you'll need to slip a short piece of 1/2 inch or so pipe over the short end to get enough leverage to loosen the plug. Getting this thing into place is a little trick, but the ball end allows you to be a little off-center which helps a bunch.
Use the short end of the wrench through a hold in the crossmember to remove the drain plug. You shouldn't need any extra leverage on this. Once its loose you may be able to use the long end to remove it faster.
Don't overtighten the plugs; that's alumunim and it will strip! I'm sure there's a torque spec but it would be darn hard to torque them accurately where they are. A good "firm one-hand" tight should work fine.
The plugs have some sort of red sealer on them, it might be good for a re-use but I cleaned them off a bit and used Teflon goop to seal them. I'm sure that Teflon tape would work as well. The goop and tape are available as plumbing supplies.
If its a Z06 there's a diff cooler, you may need to run the car a bit and top up. You should be able to do this while its up on the stands, just start it, drop it into fourth and "drive" a mile. The same applies to the transmission for Z06 and Z51s, except shift a few gears while doing so. That's actually kind of fun - reminds me of the little car rides out in front of supermarkets when I was a kid.
One thing I'll mention up front - although its called a transaxle, its really a transmission and differential bolted together. They use separate and different lubricants (transmission uses ATF). As long as you're mainly concerned with the differential clutch chatter you needn't worry about the transmission, but I'll throw in the info on that too. Some folks have found better shifting by changing to Royal Purple Syncromax, and you'll be under there anyway.
1. What type of socket is needed for the fill and drain plugs? Allen or torxs, or? What size?
It's a 10mm hex (Allen) type. You'll want a ball-end driver, either a Bondhus L-type or a short (less than 2 inch shaft) socket type (Snap-On works). Some of the socket type have fairly long (about 4 inch) shafts and won't fit.
The transmission uses a 3/8 inch square drive. Easy to get to.
2. Is it better to raise vehicle with rear wheels hanging (car on jack stands) or rear wheels on a surface (rear wheels on ramps)? I'd think it would be better to have the wheels hanging so that the axle is lower and more accessible, however on some cars this is not necessarily the case due to other interference.
The axle doesn't hang; it stays in place (IRS). Raise the vehicle so that it is approximately level or the front is slightly higher than the rear (the drain hole is at the back). Four jack stands work well, or drive the front onto ramps and then jack up the back.
If you jack up the front you'll need a low-profile "racing" jack; many won't fit under there. Jack under the crossmembers using a piece of wood or something to prevent scratching and spread the load over 2 or more ribs. Ditto for the rear, although you've got a little more room there.
Place jackstands under the crossmembers, again spanning two or more ribs. Some jackstands have v-shaped notches; these don't work well. Find the sort with a fairly flat saddle on top, or modify the V-shaped ones to a saddle.
An alternate jackstand location is under the frame, with jacking pads placed in the tie-down holes. Again, you'll want a jackstand that will firmly support the pads.
3. What is the recommended method for getting the oil into the fill hole? Seems that there may not be room to hold the lubricant bottle above the hole. Is there a recommended pump tool, or? In the old days when filling manual trannies I'd just connect a hose to the end of the lube bottle and squeeze the bottle, forcing the lube up the hose and into the trany... but often this got messy, oil would eventually leak out of the hose connection, etc. Is there a better way?
Put a 1 to 2 foot length of 1/4 inch plastic tubing on the nozzle of the bottle, with the other end in the fill hole. Then hold the bottle up between the mufflers and squeeze.
If you want to do the transmission too, a fluid pump that screws into the bottle ($5 at most auto parts stores) is the way to go. Again a plastic tube is required.
You can try the fluid pump for the diff lube, but its pretty thick to pump that way. The squeeze method worked well for me with little mess.
4. Why not mix the oil and additive together BEFORE adding it to the axle? The TSB says to drive figure 8s after the fill to mix the fluids, but it would make more sense to me to just mix 4 ounces of additive evenly to the 1.69 quarts of oil first, then add to the axle. Any good reason NOT to do this? Or just a waste of time? One concern is that I'd have to drive quite a few miles from my garage to get to a place where I can safely and legally do ten figure 8s.
I'd pre-mix it in the first bottle, not the second, so that its all delivered even if the 1.69 quarts is a little off. The figure 8s are not really to mix the fluids, they're to work the new fluid and additive in between the clutche plates. I don't think theres a problem with driving a ways to get to a figure 8 friendly zone; you've still got the old lube between the plates.
Most of the synthetic lubes (Mobil 1, Red Line, Royal Purple) say you don't need the additive, or to use it only if required. But as far as I know the only downside to using it would be slightly decreased limited-slip performance, and if you want to be sure you don't chatter that's probably the way to go.
I've got Mobil 1 75W-90 gear lube in mine, never had a chatter.
5. Does the axle really take 1.69 quarts of oil plus 4 ounces or additive? Or does it take more... or less? I know from experience that for whatever reason, the published capacity specs for trannies and rears are not always accurate.
It takes less than 2 quarts, I probably have about 1/3 of a bottle left. In any case, 2 quarts is plenty to account for minor spillage.
6. Does any part of the car need to be disassembled to gain adequate access to the fill plug? Such is not mentioned in the shop manual, but figured I'd ask just in case. Wouldn't be the first time a manual forget to mention an important step.
No, as long as you have the right tool to get the plugs out and some patience to work it into place. Let the car cool enough so that the mufflers aren't hot before starting, you'll be working around them a lot.
7. Any other tips, tricks, etc?
Once you've got the car raised, give it a couple good shoves to make sure its stable. You'd rather have the car repaired than have it fall on you - there really isn't much room under there!
Remove or loosen the fill plug before removing the drian plug. That way if you can't get the fill plug out you still have the old fluid in there!
If you're using the Bondhus L-shaped ball-end Allen wrench (about $12 a set) use the long (ball) end to remove the fill plug, you'll need to slip a short piece of 1/2 inch or so pipe over the short end to get enough leverage to loosen the plug. Getting this thing into place is a little trick, but the ball end allows you to be a little off-center which helps a bunch.
Use the short end of the wrench through a hold in the crossmember to remove the drain plug. You shouldn't need any extra leverage on this. Once its loose you may be able to use the long end to remove it faster.
Don't overtighten the plugs; that's alumunim and it will strip! I'm sure there's a torque spec but it would be darn hard to torque them accurately where they are. A good "firm one-hand" tight should work fine.
The plugs have some sort of red sealer on them, it might be good for a re-use but I cleaned them off a bit and used Teflon goop to seal them. I'm sure that Teflon tape would work as well. The goop and tape are available as plumbing supplies.
If its a Z06 there's a diff cooler, you may need to run the car a bit and top up. You should be able to do this while its up on the stands, just start it, drop it into fourth and "drive" a mile. The same applies to the transmission for Z06 and Z51s, except shift a few gears while doing so. That's actually kind of fun - reminds me of the little car rides out in front of supermarkets when I was a kid.
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Roodog (12-18-2015)
08-17-2006, 11:11 AM
#4
Melting Slicks
Thread Starter
Originally Posted by mike72
...be sure to remove the filler plug first. It would not be good to drain it and then find out you can't get the filler plug out...
Originally Posted by mike72
...also, I think the TSB says to fill with non synthetic fluid and only use the synthetic if the plates have been replaced. If you look at the TSB it shows using a part number that is different from the synthetic part number...
"Rear Axle Chatter Shudder on Turns - keywords differential fluid noise oil #PIP3559 - (Sep 22, 2005)
Rear Axle Chatter Shudder on Turns
1999-2006 Chevrolet Corvette
2004-2006 Cadillac XLR
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Rear axle chatter or shudder on turns on Chevrolet Corvette and Cadillac XLR.
Recommendation/Instructions:
If this is the first complaint for this condition flush and fill the rear axle with P/N 89021669 (in Canada 89021670) gear lube and 4 ounces of the friction modifier additive P/N 01052358 (in Canada 992694).
If this is a repeat complaint or the condition persists after the flush and fill, replace the right and left rear axle clutch packs following published service procedures.
After clutch pack replacement use 1.6 l (1.69 qt) synthetic axle lubricant GM P/N 12378261 (Canadian P/N 10953455). and 4 ounces of the friction modifier additive P/N 01052358 (in Canada 992694).
Note: 2006 Z06 equipped vehicles require 2.55 l (2.70 qt) synthetic axle lubricant GM P/N 12378261 (Canadian P/N 10953455) and approximately 190 ml (6.4 oz) limited-slip differential lubricant additive GM P/N 1052358 (Canadian P/N 992694).
Note: Export vehicles use 2.01 l (2.12 qt) synthetic axle lubricant GM P/N 12378261 (Canadian P/N 10953455) and approximately 150 ml (5.1 oz) limited-slip differential lubricant additive GM P/N 1052358 (Canadian P/N 992694).
Once the axle fluid has been changed the car must be driven in 8 - 10 SLOW figure eights to work the fluid between the clutch plates."
08-17-2006, 11:43 AM
#5
Melting Slicks
Thread Starter
Originally Posted by Buffy
Good questions - I hope these answers help. It certainly makes sense to be prepared!...
I guess the only thing that still concerns me a tad is oil type to use. I might be inclined to go with Mobil 1 or Redline (synthetics), etc, but considering the apparent need for TSB issuance on the matter, I think it's probably best to stick to exactly what the TSB outlines.
I am wondering why exactly (per the TSB) the GM synthetic oil is specified for ONLY when replacing the clutch packs. So then shall we assume, per the TSB, that ANY time the axle oil is to be changed, ever, when NOT replacing the clutch packs, that the 89021669 oil (non-synthetic I believe) is to be used? And if synthetic oil WAS used, will this cause earlier clutch pack failure or other failure? There must be a good reason for the TSB to specify this... I certainly hope this isn't just an error.
Because the manuals specify to use the GM synthetic (12378261) in the axle, but the TSB says to use the 89021669 gear oil instead (at least when not replacing the clutches), I wonder if the oil itself has something to do with the clutch pack problem?
Those who have experienced clutch pack chatter and then performed a drain / refill... what type of oil did you use, and how many miles has it been since the refill? Any more chatter, and if so, how many miles later? A failure? Maybe we can try to get an idea about what type of oil is working out best for everyone here.
Regardless, due to the nature of the problem and fact that the car may need to go back to the dealer for a clutch pack replacement under warrantee, I plan to use only GM oil, whether the 89021669 or 12378261... and 4 ounces of additive of course.
08-17-2006, 11:57 AM
#6
Melting Slicks
Thread Starter
By the way, just did some quick searching - GM part# 89021669 oil (formerly part# 12345977) is apparently "80w-90 Rear Axle Lubricant API GL-5"... no mention of "synthetic", so it appears it is not synthetic.
08-17-2006, 12:02 PM
#7
Melting Slicks
Why not just take it to a dealer and have it done under warranty. I did this a couple of weeks ago and so far it's working much better.
08-17-2006, 12:18 PM
#9
I changed fluid at 3K miles, not for chatter but "just because". I used Mobil 1 (synthetic). Now have 10K miles with no problems or chatter.
BTW, I think the GM stuff is a semi-synthetic (blended) Texaco product. Its the same stuff they specify for almost all the vehicles they make; I'm inclined to think a C6's rear end might need a better oil than an Aveo's. I know that they specified synthetic for replacement fluid on the Camaros, even though the factory fill was the same stuff.
BTW, I think the GM stuff is a semi-synthetic (blended) Texaco product. Its the same stuff they specify for almost all the vehicles they make; I'm inclined to think a C6's rear end might need a better oil than an Aveo's. I know that they specified synthetic for replacement fluid on the Camaros, even though the factory fill was the same stuff.
08-17-2006, 12:20 PM
#10
Melting Slicks
Thread Starter
Originally Posted by Silver85
Why not just take it to a dealer and have it done under warranty...
08-17-2006, 12:38 PM
#11
Team Owner
Originally Posted by Buffy
Good questions - I hope these answers help. It certainly makes sense to be prepared!
One thing I'll mention up front - although its called a transaxle, its really a transmission and differential bolted together. They use separate and different lubricants (transmission uses ATF). As long as you're mainly concerned with the differential clutch chatter you needn't worry about the transmission, but I'll throw in the info on that too. Some folks have found better shifting by changing to Royal Purple Syncromax, and you'll be under there anyway.
1. What type of socket is needed for the fill and drain plugs? Allen or torxs, or? What size?
It's a 10mm hex (Allen) type. You'll want a ball-end driver, either a Bondhus L-type or a short (less than 2 inch shaft) socket type (Snap-On works). Some of the socket type have fairly long (about 4 inch) shafts and won't fit.
The transmission uses a 3/8 inch square drive. Easy to get to.
2. Is it better to raise vehicle with rear wheels hanging (car on jack stands) or rear wheels on a surface (rear wheels on ramps)? I'd think it would be better to have the wheels hanging so that the axle is lower and more accessible, however on some cars this is not necessarily the case due to other interference.
The axle doesn't hang; it stays in place (IRS). Raise the vehicle so that it is approximately level or the front is slightly higher than the rear (the drain hole is at the back). Four jack stands work well, or drive the front onto ramps and then jack up the back.
If you jack up the front you'll need a low-profile "racing" jack; many won't fit under there. Jack under the crossmembers using a piece of wood or something to prevent scratching and spread the load over 2 or more ribs. Ditto for the rear, although you've got a little more room there.
Place jackstands under the crossmembers, again spanning two or more ribs. Some jackstands have v-shaped notches; these don't work well. Find the sort with a fairly flat saddle on top, or modify the V-shaped ones to a saddle.
An alternate jackstand location is under the frame, with jacking pads placed in the tie-down holes. Again, you'll want a jackstand that will firmly support the pads.
3. What is the recommended method for getting the oil into the fill hole? Seems that there may not be room to hold the lubricant bottle above the hole. Is there a recommended pump tool, or? In the old days when filling manual trannies I'd just connect a hose to the end of the lube bottle and squeeze the bottle, forcing the lube up the hose and into the trany... but often this got messy, oil would eventually leak out of the hose connection, etc. Is there a better way?
Put a 1 to 2 foot length of 1/4 inch plastic tubing on the nozzle of the bottle, with the other end in the fill hole. Then hold the bottle up between the mufflers and squeeze.
If you want to do the transmission too, a fluid pump that screws into the bottle ($5 at most auto parts stores) is the way to go. Again a plastic tube is required.
You can try the fluid pump for the diff lube, but its pretty thick to pump that way. The squeeze method worked well for me with little mess.
4. Why not mix the oil and additive together BEFORE adding it to the axle? The TSB says to drive figure 8s after the fill to mix the fluids, but it would make more sense to me to just mix 4 ounces of additive evenly to the 1.69 quarts of oil first, then add to the axle. Any good reason NOT to do this? Or just a waste of time? One concern is that I'd have to drive quite a few miles from my garage to get to a place where I can safely and legally do ten figure 8s.
I'd pre-mix it in the first bottle, not the second, so that its all delivered even if the 1.69 quarts is a little off. The figure 8s are not really to mix the fluids, they're to work the new fluid and additive in between the clutche plates. I don't think theres a problem with driving a ways to get to a figure 8 friendly zone; you've still got the old lube between the plates.
Most of the synthetic lubes (Mobil 1, Red Line, Royal Purple) say you don't need the additive, or to use it only if required. But as far as I know the only downside to using it would be slightly decreased limited-slip performance, and if you want to be sure you don't chatter that's probably the way to go.
I've got Mobil 1 75W-90 gear lube in mine, never had a chatter.
5. Does the axle really take 1.69 quarts of oil plus 4 ounces or additive? Or does it take more... or less? I know from experience that for whatever reason, the published capacity specs for trannies and rears are not always accurate.
It takes less than 2 quarts, I probably have about 1/3 of a bottle left. In any case, 2 quarts is plenty to account for minor spillage.
6. Does any part of the car need to be disassembled to gain adequate access to the fill plug? Such is not mentioned in the shop manual, but figured I'd ask just in case. Wouldn't be the first time a manual forget to mention an important step.
No, as long as you have the right tool to get the plugs out and some patience to work it into place. Let the car cool enough so that the mufflers aren't hot before starting, you'll be working around them a lot.
7. Any other tips, tricks, etc?
Once you've got the car raised, give it a couple good shoves to make sure its stable. You'd rather have the car repaired than have it fall on you - there really isn't much room under there!
Remove or loosen the fill plug before removing the drian plug. That way if you can't get the fill plug out you still have the old fluid in there!
If you're using the Bondhus L-shaped ball-end Allen wrench (about $12 a set) use the long (ball) end to remove the fill plug, you'll need to slip a short piece of 1/2 inch or so pipe over the short end to get enough leverage to loosen the plug. Getting this thing into place is a little trick, but the ball end allows you to be a little off-center which helps a bunch.
Use the short end of the wrench through a hold in the crossmember to remove the drain plug. You shouldn't need any extra leverage on this. Once its loose you may be able to use the long end to remove it faster.
Don't overtighten the plugs; that's alumunim and it will strip! I'm sure there's a torque spec but it would be darn hard to torque them accurately where they are. A good "firm one-hand" tight should work fine.
The plugs have some sort of red sealer on them, it might be good for a re-use but I cleaned them off a bit and used Teflon goop to seal them. I'm sure that Teflon tape would work as well. The goop and tape are available as plumbing supplies.
If its a Z06 there's a diff cooler, you may need to run the car a bit and top up. You should be able to do this while its up on the stands, just start it, drop it into fourth and "drive" a mile. The same applies to the transmission for Z06 and Z51s, except shift a few gears while doing so. That's actually kind of fun - reminds me of the little car rides out in front of supermarkets when I was a kid.
One thing I'll mention up front - although its called a transaxle, its really a transmission and differential bolted together. They use separate and different lubricants (transmission uses ATF). As long as you're mainly concerned with the differential clutch chatter you needn't worry about the transmission, but I'll throw in the info on that too. Some folks have found better shifting by changing to Royal Purple Syncromax, and you'll be under there anyway.
1. What type of socket is needed for the fill and drain plugs? Allen or torxs, or? What size?
It's a 10mm hex (Allen) type. You'll want a ball-end driver, either a Bondhus L-type or a short (less than 2 inch shaft) socket type (Snap-On works). Some of the socket type have fairly long (about 4 inch) shafts and won't fit.
The transmission uses a 3/8 inch square drive. Easy to get to.
2. Is it better to raise vehicle with rear wheels hanging (car on jack stands) or rear wheels on a surface (rear wheels on ramps)? I'd think it would be better to have the wheels hanging so that the axle is lower and more accessible, however on some cars this is not necessarily the case due to other interference.
The axle doesn't hang; it stays in place (IRS). Raise the vehicle so that it is approximately level or the front is slightly higher than the rear (the drain hole is at the back). Four jack stands work well, or drive the front onto ramps and then jack up the back.
If you jack up the front you'll need a low-profile "racing" jack; many won't fit under there. Jack under the crossmembers using a piece of wood or something to prevent scratching and spread the load over 2 or more ribs. Ditto for the rear, although you've got a little more room there.
Place jackstands under the crossmembers, again spanning two or more ribs. Some jackstands have v-shaped notches; these don't work well. Find the sort with a fairly flat saddle on top, or modify the V-shaped ones to a saddle.
An alternate jackstand location is under the frame, with jacking pads placed in the tie-down holes. Again, you'll want a jackstand that will firmly support the pads.
3. What is the recommended method for getting the oil into the fill hole? Seems that there may not be room to hold the lubricant bottle above the hole. Is there a recommended pump tool, or? In the old days when filling manual trannies I'd just connect a hose to the end of the lube bottle and squeeze the bottle, forcing the lube up the hose and into the trany... but often this got messy, oil would eventually leak out of the hose connection, etc. Is there a better way?
Put a 1 to 2 foot length of 1/4 inch plastic tubing on the nozzle of the bottle, with the other end in the fill hole. Then hold the bottle up between the mufflers and squeeze.
If you want to do the transmission too, a fluid pump that screws into the bottle ($5 at most auto parts stores) is the way to go. Again a plastic tube is required.
You can try the fluid pump for the diff lube, but its pretty thick to pump that way. The squeeze method worked well for me with little mess.
4. Why not mix the oil and additive together BEFORE adding it to the axle? The TSB says to drive figure 8s after the fill to mix the fluids, but it would make more sense to me to just mix 4 ounces of additive evenly to the 1.69 quarts of oil first, then add to the axle. Any good reason NOT to do this? Or just a waste of time? One concern is that I'd have to drive quite a few miles from my garage to get to a place where I can safely and legally do ten figure 8s.
I'd pre-mix it in the first bottle, not the second, so that its all delivered even if the 1.69 quarts is a little off. The figure 8s are not really to mix the fluids, they're to work the new fluid and additive in between the clutche plates. I don't think theres a problem with driving a ways to get to a figure 8 friendly zone; you've still got the old lube between the plates.
Most of the synthetic lubes (Mobil 1, Red Line, Royal Purple) say you don't need the additive, or to use it only if required. But as far as I know the only downside to using it would be slightly decreased limited-slip performance, and if you want to be sure you don't chatter that's probably the way to go.
I've got Mobil 1 75W-90 gear lube in mine, never had a chatter.
5. Does the axle really take 1.69 quarts of oil plus 4 ounces or additive? Or does it take more... or less? I know from experience that for whatever reason, the published capacity specs for trannies and rears are not always accurate.
It takes less than 2 quarts, I probably have about 1/3 of a bottle left. In any case, 2 quarts is plenty to account for minor spillage.
6. Does any part of the car need to be disassembled to gain adequate access to the fill plug? Such is not mentioned in the shop manual, but figured I'd ask just in case. Wouldn't be the first time a manual forget to mention an important step.
No, as long as you have the right tool to get the plugs out and some patience to work it into place. Let the car cool enough so that the mufflers aren't hot before starting, you'll be working around them a lot.
7. Any other tips, tricks, etc?
Once you've got the car raised, give it a couple good shoves to make sure its stable. You'd rather have the car repaired than have it fall on you - there really isn't much room under there!
Remove or loosen the fill plug before removing the drian plug. That way if you can't get the fill plug out you still have the old fluid in there!
If you're using the Bondhus L-shaped ball-end Allen wrench (about $12 a set) use the long (ball) end to remove the fill plug, you'll need to slip a short piece of 1/2 inch or so pipe over the short end to get enough leverage to loosen the plug. Getting this thing into place is a little trick, but the ball end allows you to be a little off-center which helps a bunch.
Use the short end of the wrench through a hold in the crossmember to remove the drain plug. You shouldn't need any extra leverage on this. Once its loose you may be able to use the long end to remove it faster.
Don't overtighten the plugs; that's alumunim and it will strip! I'm sure there's a torque spec but it would be darn hard to torque them accurately where they are. A good "firm one-hand" tight should work fine.
The plugs have some sort of red sealer on them, it might be good for a re-use but I cleaned them off a bit and used Teflon goop to seal them. I'm sure that Teflon tape would work as well. The goop and tape are available as plumbing supplies.
If its a Z06 there's a diff cooler, you may need to run the car a bit and top up. You should be able to do this while its up on the stands, just start it, drop it into fourth and "drive" a mile. The same applies to the transmission for Z06 and Z51s, except shift a few gears while doing so. That's actually kind of fun - reminds me of the little car rides out in front of supermarkets when I was a kid.
My understanding is the factory fill from GM is synthetic so that is what should be in there now.
If you use Redline no additional friction modifier is necessary to add.
I was going to change the fluid to get any particles out of it but I was told there is already a magnet in there and there is no need to change rear diff. oil.
In addition to this latest news TSB about clutch packs and rear end noises I will not change it per manual unless there is a need to or leak/problem. I have not had this chattering problem. If I did I would go with Amsoil or Redline. "If it ain't broke don't fix it".
08-17-2006, 12:58 PM
#12
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The reason I pointed out the fluid type in the TSB is because when I experienced the problem the first time I did not pay attention and put in Mobil 1 75-90. The problem came back within a month. When i re-read the TSB I saw the different part number and used non synth. and the problem has not come back.
08-17-2006, 01:46 PM
#14
Originally Posted by LS WON
Do you have any pics of this whole socket set up in #1 above?
...
...
Sets of the L-shaped ball-end Allen wrenches are available for about $10-15 from Northern Tool, Sears, whatever. Set of ball-end Allen sockets are available for more money from various places. Here are a couple of links to Snap-On (who make good but expensive tools):
L-shaped set: http://buy1.snapon.com/catalog/item....re&dir=catalog
Socket bit: http://buy1.snapon.com/catalog/item....re&dir=catalog
Just avoid this type, as they may be too long to fit:
http://buy1.snapon.com/catalog/item....re&dir=catalog
The bottom plug comes out pretty easily by using an L-handle Allen wrench through a cutout in the crossmember. The upper one is a bit trickier as there's not enough room to move the wrench, so it has to be approached from behind and you can't get a straight shot at it. This is where the ball-end driver really comes in handy. It might be possible using a conventional square-end type, but it would be a real knuckle-buster.
I'll see if I can get some pictures under the car, but I'm not sure when I'll be able to do that.
08-17-2006, 01:55 PM
#15
Team Owner
Originally Posted by Buffy
I mention Bondhus in particular because they were the first with the ball-end drivers; now pretty much everybody has them. The advantage to the ball-end is that unlike a conventional Allen it doesn't have to be perfectly straight into the plug, which is hard to do on the C6.
Sets of the L-shaped ball-end Allen wrenches are available for about $10-15 from Northern Tool, Sears, whatever. Set of ball-end Allen sockets are available for more money from various places. Here are a couple of links to Snap-On (who make good but expensive tools):
L-shaped set: http://buy1.snapon.com/catalog/item....re&dir=catalog
Socket bit: http://buy1.snapon.com/catalog/item....re&dir=catalog
Just avoid this type, as they may be too long to fit:
http://buy1.snapon.com/catalog/item....re&dir=catalog
The bottom plug comes out pretty easily by using an L-handle Allen wrench through a cutout in the crossmember. The upper one is a bit trickier as there's not enough room to move the wrench, so it has to be approached from behind and you can't get a straight shot at it. This is where the ball-end driver really comes in handy. It might be possible using a conventional square-end type, but it would be a real knuckle-buster.
I'll see if I can get some pictures under the car, but I'm not sure when I'll be able to do that.
Sets of the L-shaped ball-end Allen wrenches are available for about $10-15 from Northern Tool, Sears, whatever. Set of ball-end Allen sockets are available for more money from various places. Here are a couple of links to Snap-On (who make good but expensive tools):
L-shaped set: http://buy1.snapon.com/catalog/item....re&dir=catalog
Socket bit: http://buy1.snapon.com/catalog/item....re&dir=catalog
Just avoid this type, as they may be too long to fit:
http://buy1.snapon.com/catalog/item....re&dir=catalog
The bottom plug comes out pretty easily by using an L-handle Allen wrench through a cutout in the crossmember. The upper one is a bit trickier as there's not enough room to move the wrench, so it has to be approached from behind and you can't get a straight shot at it. This is where the ball-end driver really comes in handy. It might be possible using a conventional square-end type, but it would be a real knuckle-buster.
I'll see if I can get some pictures under the car, but I'm not sure when I'll be able to do that.
for the info so only 2 tool parts are needed the 10MM Allen wrench and the 10 MM bit?The Snap-On Tools are mail order only? I can easily get Craftsman so how does that compare to the Snap-On?
Last edited by LS WON; 08-17-2006 at 02:00 PM.
08-17-2006, 03:09 PM
#16
Melting Slicks
Thread Starter
Only problem is that IF the plug is really in there super tight, using a ball-end allen on an angle may only serve to strip the plug... or the tool. Not enough grip for a high torque situation. Would be best to get into the plug dead straight with a non-ball wrench if at all possible... but sounds like that may be hard or impossible.
I wonder if a customized socket would work... could always take a socket and just cut or grind the tip down so it is super short. Or... even an L-shaped wrench with its short side cut down... would allow even more clearance. You could almost get the handle of the wrench flat up against the case. (I'm talking without seeing the plug.)
Well, in any case, I'll try to have all these 10mm allen configurations nearby when I go to do the oil change.
For anyone using a standard L-shaped allen key wrench, it is indeed critical to have a small pipe to use as a leverage handle... otherwise you WILL break your knuckles or hurt your hand one way or another. I use the socket type all the time unless it isn't possible.
As for sealing the plugs... I learned from a good plumber that teflon tape alone is often not good enough. I also know this from experience... at least when it comes to water pipes. My plumber friend (meticulous ace with 40 years of experience) uses teflon tape PLUS a small amount of non-hardening pipe goop... I've tried this and it works 100% every time... on water pipes. Now on a rear axle case holding oil that gets real hot... not sure. Maybe the pipe goop would fail. Permatex must make some sort of good silicon gasket sealer stuff that is more appropriate... and make sure not to use too much.
I wonder if a customized socket would work... could always take a socket and just cut or grind the tip down so it is super short. Or... even an L-shaped wrench with its short side cut down... would allow even more clearance. You could almost get the handle of the wrench flat up against the case. (I'm talking without seeing the plug.)
Well, in any case, I'll try to have all these 10mm allen configurations nearby when I go to do the oil change.
For anyone using a standard L-shaped allen key wrench, it is indeed critical to have a small pipe to use as a leverage handle... otherwise you WILL break your knuckles or hurt your hand one way or another. I use the socket type all the time unless it isn't possible.
As for sealing the plugs... I learned from a good plumber that teflon tape alone is often not good enough. I also know this from experience... at least when it comes to water pipes. My plumber friend (meticulous ace with 40 years of experience) uses teflon tape PLUS a small amount of non-hardening pipe goop... I've tried this and it works 100% every time... on water pipes. Now on a rear axle case holding oil that gets real hot... not sure. Maybe the pipe goop would fail. Permatex must make some sort of good silicon gasket sealer stuff that is more appropriate... and make sure not to use too much.
08-17-2006, 03:16 PM
#17
Team Owner
I saw under the C-6 where the differential plugs are. It doesn't look that difficult perhaps the top one may be a little challenging but I haven't changed it because I have not had any problems with it per manual it states you need not change it unless there is a problem or a leak. So now with that TSB out on the rear end I will wait.
08-17-2006, 03:35 PM
#18
Originally Posted by LS WON
for the info so only 2 tool parts are needed the 10MM Allen wrench and the 10 MM bit?The Snap-On Tools are mail order only? I can easily get Craftsman so how does that compare to the Snap-On?
Snap-On mainly sells through local dealers who drive around in trucks, visiting garages and so on. Look in the phone book, there's probably one in your area and he'll meet you somewhere or come by your house if you call him. Sort of like a drug dealer, and the tools can be as expensive and addictive as crack! At least that's what my wife says
On the other hand, this can be very handy if you're half-way through a job and break a tool or find out you need a left-handed metric adjustable wrench!
The Snap-on tools are good, and they have a wide selection - need 5-sided sockets? But they are expensive, and I can't justify them for most things. I do have some for what I consider "very critical" things - flare nut wrenches, for example, because its really easy to round off a soft flare nut, and the Snap-on flare nut wrenches are really nice. But most of the time I use tools that cost less than the car I'm working on
I will note that the prices on the web site are higher than what most of the dealers sell the stuff for.
08-17-2006, 03:40 PM
#19
Team Owner
Originally Posted by Buffy
Either the L-wrench or the bit - you won't need both. And you should be able to get either at Sears. I just used Snap-On examples because they have a good on-line catalog.
Snap-On mainly sells through local dealers who drive around in trucks, visiting garages and so on. Look in the phone book, there's probably one in your area and he'll meet you somewhere or come by your house if you call him. Sort of like a drug dealer, and the tools can be as expensive and addictive as crack! At least that's what my wife says
On the other hand, this can be very handy if you're half-way through a job and break a tool or find out you need a left-handed metric adjustable wrench!
The Snap-on tools are good, and they have a wide selection - need 5-sided sockets? But they are expensive, and I can't justify them for most things. I do have some for what I consider "very critical" things - flare nut wrenches, for example, because its really easy to round off a soft flare nut, and the Snap-on flare nut wrenches are really nice. But most of the time I use tools that cost less than the car I'm working on
I will note that the prices on the web site are higher than what most of the dealers sell the stuff for.
Snap-On mainly sells through local dealers who drive around in trucks, visiting garages and so on. Look in the phone book, there's probably one in your area and he'll meet you somewhere or come by your house if you call him. Sort of like a drug dealer, and the tools can be as expensive and addictive as crack! At least that's what my wife says
On the other hand, this can be very handy if you're half-way through a job and break a tool or find out you need a left-handed metric adjustable wrench!
The Snap-on tools are good, and they have a wide selection - need 5-sided sockets? But they are expensive, and I can't justify them for most things. I do have some for what I consider "very critical" things - flare nut wrenches, for example, because its really easy to round off a soft flare nut, and the Snap-on flare nut wrenches are really nice. But most of the time I use tools that cost less than the car I'm working on
I will note that the prices on the web site are higher than what most of the dealers sell the stuff for.
08-17-2006, 03:50 PM
#20
Melting Slicks
Thread Starter
Originally Posted by mike72
The reason I pointed out the fluid type in the TSB is because when I experienced the problem the first time I did not pay attention and put in Mobil 1 75-90. The problem came back within a month. When i re-read the TSB I saw the different part number and used non synth. and the problem has not come back.
Thanks for the info! This is significant information. I wonder what it is about the synth oil that does not cure the noise issue. This is the case with your experience, and "confirmed" by GM's TSB.Do you happen to remember how many miles you put on the car from the time you added the Mobil 1 to the time the noise came back? Also, how many miles do you have on the non-synth oil now?
Thanks
