Toque

Guys:

So... I was cleaning my car last weekend and noticed my rear diff had some wet oil on it a bit with dust mixed all on it. . I got it cleaned up and I plan to watch it closely. There is no oil on my garage floor so this is a slow leak. I want to figure out if its the Drivers axle seal, or the oring around the diff cover. I am leaning towards the axle seal because its common to go out on the C5's, and there was oil/dirt on my drivers axle where there was none on my passenger axle.

I am going to try to look tonight to see if its leaking out the breather on the top of the diff. I doubt it though, because I don't drive my car hard enough for the oil to get that hot.

I found that these are the parts required to fix this.
88996703 (new revision) output shaft(s) center seal (all C5 carriers)
89047953 (new revision) side plate outer "O" ring seal (use with anerobic sealer)
1052942 Anaerobic sealant

If its an axle leak then you need the axle seal, and if its leaking around the cover of the diff then you need the Oring.
Does anyone know how the Anaerobic sealant is used with the oring for the diff cover ?

I found the GM TSB:
http://www.corvetteactioncenter.com/...over+Flange%29

I found a decent procedure from the DIY thread...
http://www.cajundude.com/outputshaftseal.htm

If at all possible I refuse to spend big $$ to do something I can fix myself.

I love this forum for info !!!

Wish me luck over the next few weeks trying to figure out where my leak is, and fixing it myself. I will have pics posted when I fiure this out.

I want to thank forum member "Subdriver" for giving me guidance on this issue over the last couple days. He has changed his axle seal a few times, and gave me confidence I can do it too ! I am getting some Amsoil from him to replace my Rear Diff, and tranny fluid...

Toque

CamminC5

This is an easy job don't pay someone to do it. I pulled my diff carrier and swapped the left output shaft leaving the diff case in the car. It took a few hours. Just drop the rear cradle and it's all gravy. Good luck!

PS. That sealer is around $20. GM is very proud of it.

Bill Curlee

If you just have a very small seep, hell,,, I wouldn't even mess with it. Wait till its worse. Its most likely just the output shaft seal. Just remove the seal and pop a new one in when your ready to fix it.

BC

Toque

Thanks for the support guys !

Is it really that easy to separate the drive shaft from the rear diff ?

From what I'm reading about this seal..... its not a matter of "IF" it will leak, but a matter of "WHEN" it will leak...

I welcome any tips that I can use to do this. I want to take lots of details pics, and post another procedure on my web site. Just another way I like to give back to the forum...

Toque

C66 Racing

Toque,
Thanks for the mention and glad to have helped. Sharing info on a few of the key points here and answering your last PMs.

In my experience and that of those I know, it has always been the axle seal. Not saying it couldn't be the side plate, but I don't personally know anyone who has had that and everyone I track with has had the left axle seal problem.

I use and carry as a spare:
88996703 (new revision) output shaft(s) center seal (all C5 carriers)

The axle nut is a very uncommon size and it took me a while to get one. Mine is 34mm impact wrench socket I picked up at a Napa store. None of my other tools sources (e.g. Sears, Home Depot, Lowes, etc) had one - but this was years ago, so maybe more common now.

And, as mentioned in my PM, I didn't (don't) drop the rear cradle - just pop off the lower a-arm ball joint and pull out the a-arm enough to get the half shaft out. You'll need a ball joint splitter for this. In the DIY link you posted above, the cajundude removes the top a-arm from the frame and rotates the upright out that way, so clearly either doing the lower end or upper end can work. I think I'm comfortable popping the lower ball joint because I have to do that for other things (like replacing the wheel bearing - another fairly easy DIY project). You'd think I'd remember this better, especially since I just did this exact repair a few weeks ago, but I'm pretty sure that if you go the lower ball joint route you'll have to unbolt the lower end of the shock so the lower a-arm can drop enough to get the upright off the lower a-arm and you'll need to disconnect the tie rod so you can swing the a-arm out away from the half shaft. Neither of those is hard.

In answer to your questions posted above, yes, once you get the a-arm out of the way (which captures the outer end of the half shaft), the half just just pulls out of the diff.

If any are wondering, these are the products that Toque is picking up for his Z06 and the same ones I run in my SCCA T1 class 02 Z06:
Tranny: AMSOIL Torque-Drive Synthetic Transmission Fluid (Product Code ATD1G) (need 1 gal)
Diff: AMSOIL Severe Gear Extreme Pressure Synthetic 75w90 (Product Code SVGQT) (need 2 quarts)
Note: The Severe Gear 75w90 comes with friction modifier already in it and using extra is not normally needed to prevent diff chatter in the C5 (not so for the C6). I run this fluid in my 02 Z06 with no extra additive and do not have diff chatter.

For the DIYer, this comes in handy:
AMSOIL Hand Pump (Product Code G2039)
Note: I recommend removing the plastic tip from the nozzle - not needed and can pop off where you don't want it to.

Finally, my "day" job has prevented me from being on the forum much this past year, but for any that email or PM, I will get back to you in the evening. But, I'm always happy to get AMSOIL products to forum members for dealer wholesale, about 25% below retail, via the AMSOIL Preferred Customer Program.

Drop me a PM if interested.

MyEBc5Z

Does the ams gear oil need the limited slip additive?

CamminC5

Sorry if I was misunderstood, but you don't have to drop the cradle to swap the seals. I went ahead and upgraded my outputshafts while I was back there. That requires un bolting the rearend from the trans. I also don't think the cover seal is the culprit only the axle seal, but while you in there you might as well add new ones especially if you have some miles on your setup.

Either way this is an easy job!

imavettegirl

no.

C66 Racing

For the C5 no.

For the C6, I recommend at least half a bottle of the Slip Lock Additive (or GM equivalent). The AMSOIL Severe Gear comes with friction modifier already in it and extra is not needed to prevent diff chatter in the vast majority of C5s. I run that fluid in my 02 Z06 without extra additive. But, GM changed the diff clutch plates on the C6 (and needed to release a whole new fluid as a result - and that after the fact). While many C6 owners run the Severe Gear straight up and report no diff chatter, because of the problems GM has had with C6 diff chatter, most C6 owners add a few ounces of friction modifier to ensure they don't have chatter.

Toque

Everyone:

Well... I got under the car tonight. I got my spot light under looking over the rear diff. I only drove it about 50 miles last weekend so this is still up in the air...

First off the passenger side is very clean and was never dirty with oil/dirt.

I have never had a drop of any fluid on my garage floor.

The bottom half of the drivers side diff is still clean as a whistle after I cleaned it last weekend.

That's when I noticed with the spot light that the top half of the drivers side diff had some caked on oil/dirt in it (Just like the bottom half did last weekend). I reached up there and felt the diff vent and I could feel the oil on it. Maybe I have been running my car harder than I thought....

I have owned my car since new and I know the diff has never been serviced or fluids changed. Maybe it was overfilled from the factory.. who knows....

I got everything clean for now (entire drivers side diff). I am starting to lean towards this being a bit of oil coming out the top vent of the Diff. This is normal I hear. I am going to keep a close eye on this. I got my fingers crossed that it was just a bit of oil coming out of the vent...



I got prepped this week for this job by getting:
1.) 2x GM Output Axle seals - 88996703 (just in case )
2.) Kent Moore J-46405 Axle Seal Installer (Fleebay)

I guess I'm ready if/when the problem does appear on my ride...


"SubDriver" hooked me up with:
1.) Amsoil Rear Diff Fluid (I needed 2x bottles)
http://www.c66racing-synthetics.com/...tins/SVGPB.htm
2.) Amsoil Transmission Fluid (6 speed). (I needed one gallon)
http://www.c66racing-synthetics.com/...tins/ATDPB.htm
3.) Amsoil Slip Lock (1x tube - Just in case )
http://www.c66racing-synthetics.com/...tins/ADAPB.htm
4.) Amsoil Hand Pumps (I got 2x - one for Diff fluid, and one for Tranny fluid)
http://www.c66racing-synthetics.com/...ns/G2039PB.htm


I guess I'm going to change out my Diff and Tranny fluid tonight. I'll post links to the procedure I write up on doing these fluid changes !

Thanks again for your help Brad (Subdriver). I appreciate you listening to be rambling more than you know....

Toque

WKMCD

Good catch! Even vapors out of the vent will collect dust/crud/crap.

These rears will eventually leak. If it's not making a mess and is more of a small "weep", I'd leave it alone.

C66 Racing

My pleasure. Hope the fluid you had/have on the driver's side is in fact the vent and not the left axle seal. But, if it turns out to be the axle seal, you are well prepared to deal with it.

Toque

Thanks guys !

I changed out the Diff and Tranny fluid last night.

I was out this morning doing 10++ figure 8's in the school parking lot. People must have thought I was nuts driving by watching me... . No rear end noise at all. I did add 1/3 of the bottle of Slip Lock to the Diff though (Just to be safe...) Shifter feels a "little" easier than before. It was only a 10 min drive though. I plan to take it out tonight for longer drive. My 7yr old Z06 only had 19K miles on it so I did not expect a big change. The Diff and tranny fluids were very dark in color though. No leaks on the garage floor after the drive this morning and 4 hours later...

I have to go easy (no WOT) for 300 miles as per the manual... This might take a while with it being winter, bad weather on the way, and I only find time on the weekend to cruise. At least I don't have a big Corvette event coming soon... . Plenty of time to work the new stuff in...

I got lots of pics last night from the Diff and tranny fluid change. Plan to post procedures to my web site in the next few days when I can get time to put it all together, and write it out.

Toque

Toque

Here is what I did Friday night....

http://forums.corvetteforum.com/c5-t...id-change.html

and

http://forums.corvetteforum.com/c5-t...id-change.html

Hope this helps someone !
TOque

C66 Racing

Toque,
Those are both great writeups that will help many and I hope let many know that changing diff and tranny fluids on a C5 really isn't that hard.

Toque

I agree. Once I really got in there working on this I thought to myself "wow there is nothing to this". Hopefully I demonstrated that in the procedures.

Toque