Slight grinding going into fourth
07-27-2014, 08:02 PM
#1
Pro
Thread Starter
Slight grinding going into fourth
64 with a 400hp reworked 327, stock four speed tranny. First through third are very smooth. The last few weekends noticed a slight grind going into fourth at speed. Just a minor issue but worried about a major malfunction.
Besides gas and wax nothing done to it the last two months. Any ideas guys?
Besides gas and wax nothing done to it the last two months. Any ideas guys?
07-27-2014, 08:05 PM
#2
Le Mans Master
64 with a 400hp reworked 327, stock four speed tranny. First through third are very smooth. The last few weekends noticed a slight grind going into fourth at speed. Just a minor issue but worried about a major malfunction.
Besides gas and wax nothing done to it the last two months. Any ideas guys?
Besides gas and wax nothing done to it the last two months. Any ideas guys?
07-28-2014, 01:44 AM
#3
If it's been shifting fine before this and you haven't touched the linkage, agreed its a bad synchro. Fix it before you need a gear too. You'll be happy you avoided the extra cost.
07-28-2014, 06:03 PM
#5
Don't ride with your hand on the shifter in fourth gear! It WILL wear the engagement fork and the clutch hub and cause the problem you describe. If that's what you have been doing, then just skip to the end..
After each one of these checks take a test drive.
First things first, check the cotton pickin oil!! Its a plug on the passenger side, crack it loose and oil should run out. If not, fill it until it does with some 75 weight gear oil.
If its a factory shifter check the holes in the levers to make sure they are not oblong and check the actual linkage arms to make sure they are not worn down. If they aren't adjust linkage according to chassis service manual.
These parts get worked millions of times throughout a vehicles life, and they are subject to wear and replacement as is anything else.
If you have a hurst shifter and you used the plastic bushings, order the hurst pit pack. Adjust linkage with a 1/4 -20 bolt four inches long. That plastic pin has too much slop for me...
Summit Racing Part Number:
HUU-3327302
Those are metal bushings that are not subject to much wear. I do grease em once a year. (They are in my Z28 and THAT linkage adjusted properly with the bolt hasn't exactly seen an easy life with me.) But my throws on the stock hurst shifter in that car at 8k rpm are hardly a miss..
Assuming that all of that checks out and is in good working order, you may can then attempt to adjust your clutch linkage. Especially if you are getting a grinding action in reverse. (unsynchronized).
NOW, if you have gone through these checks and everything else above is fine, but are still getting the grinding, then your fourth gear synchronizer is going out or your fork and clutch hub are worn out which means you have to pull the tranny and rebuild it. Make sure you use the torque lock sliders and new forks if you get to this point.
Let us know how it turns out and what fixes the problem..
Tony
After each one of these checks take a test drive.
First things first, check the cotton pickin oil!! Its a plug on the passenger side, crack it loose and oil should run out. If not, fill it until it does with some 75 weight gear oil.
If its a factory shifter check the holes in the levers to make sure they are not oblong and check the actual linkage arms to make sure they are not worn down. If they aren't adjust linkage according to chassis service manual.
These parts get worked millions of times throughout a vehicles life, and they are subject to wear and replacement as is anything else.
If you have a hurst shifter and you used the plastic bushings, order the hurst pit pack. Adjust linkage with a 1/4 -20 bolt four inches long. That plastic pin has too much slop for me...
Summit Racing Part Number:
HUU-3327302
Those are metal bushings that are not subject to much wear. I do grease em once a year. (They are in my Z28 and THAT linkage adjusted properly with the bolt hasn't exactly seen an easy life with me.) But my throws on the stock hurst shifter in that car at 8k rpm are hardly a miss..
Assuming that all of that checks out and is in good working order, you may can then attempt to adjust your clutch linkage. Especially if you are getting a grinding action in reverse. (unsynchronized).
NOW, if you have gone through these checks and everything else above is fine, but are still getting the grinding, then your fourth gear synchronizer is going out or your fork and clutch hub are worn out which means you have to pull the tranny and rebuild it. Make sure you use the torque lock sliders and new forks if you get to this point.
Let us know how it turns out and what fixes the problem..
Tony
07-28-2014, 07:23 PM
#6
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If it was mine? And the transmission fluid was unknown? I'd drain it and put the oil in the transmission as specified in the owner's manual and see if the problem didn't go away. Seems like some of these guys like to re-engineer what Chevrolet spec'd way back when and come up with shifting problems. Things like the latest whizz bang transmission fluid they heard about on a *** website or other automotive website.
If it continues to scrape a little between 3-4 upshift, I'd drive on and just slow down the shift a little. That's much better than the labor/cost of pulling the transmission and replacing parts.
My truck ('95 model) five speed has scraped between 2-3 since it was new. That was 150K miles ago. No better, no worse now. My 2001 car has scraped between 2-3 ever since I've had it. I've owned it 5 years and it hasn't gotten any worse. All I do is slow down the upshift a little and it doesn't scrape.
Word to the wise.................
If it continues to scrape a little between 3-4 upshift, I'd drive on and just slow down the shift a little. That's much better than the labor/cost of pulling the transmission and replacing parts.
My truck ('95 model) five speed has scraped between 2-3 since it was new. That was 150K miles ago. No better, no worse now. My 2001 car has scraped between 2-3 ever since I've had it. I've owned it 5 years and it hasn't gotten any worse. All I do is slow down the upshift a little and it doesn't scrape.
Word to the wise.................
Last edited by MikeM; 07-28-2014 at 07:26 PM.
07-28-2014, 07:31 PM
#7
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If it was mine? And the transmission fluid was unknown? I'd drain it and put the oil in the transmission as specified in the owner's manual and see if the problem didn't go away. Seems like some of these guys like to re-engineer what Chevrolet spec'd way back when and come up with shifting problems. Things like the latest whizz bang transmission fluid they heard about on a *** website or other automotive website.
If it continues to scrape a little between 3-4 upshift, I'd drive on and just slow down the shift a little. That's much better than the labor/cost of pulling the transmission and replacing parts.
My truck ('95 model) five speed has scraped between 2-3 since it was new. That was 150K miles ago. No better, no worse now. My 2001 car has scraped between 2-3 ever since I've had it. I've owned it 5 years and it hasn't gotten any worse. All I do is slow down the upshift a little and it doesn't scrape.
Word to the wise.................
If it continues to scrape a little between 3-4 upshift, I'd drive on and just slow down the shift a little. That's much better than the labor/cost of pulling the transmission and replacing parts.
My truck ('95 model) five speed has scraped between 2-3 since it was new. That was 150K miles ago. No better, no worse now. My 2001 car has scraped between 2-3 ever since I've had it. I've owned it 5 years and it hasn't gotten any worse. All I do is slow down the upshift a little and it doesn't scrape.
Word to the wise.................
07-28-2014, 09:38 PM
#8
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07-29-2014, 05:45 AM
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07-30-2014, 12:24 PM
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Don't ride with your hand on the shifter in fourth gear! It WILL wear the engagement fork and the clutch hub and cause the problem you describe. If that's what you have been doing, then just skip to the end..
After each one of these checks take a test drive.
First things first, check the cotton pickin oil!! Its a plug on the passenger side, crack it loose and oil should run out. If not, fill it until it does with some 75 weight gear oil.
If its a factory shifter check the holes in the levers to make sure they are not oblong and check the actual linkage arms to make sure they are not worn down. If they aren't adjust linkage according to chassis service manual.
These parts get worked millions of times throughout a vehicles life, and they are subject to wear and replacement as is anything else.
If you have a hurst shifter and you used the plastic bushings, order the hurst pit pack. Adjust linkage with a 1/4 -20 bolt four inches long. That plastic pin has too much slop for me...
Summit Racing Part Number:
HUU-3327302
Those are metal bushings that are not subject to much wear. I do grease em once a year. (They are in my Z28 and THAT linkage adjusted properly with the bolt hasn't exactly seen an easy life with me.) But my throws on the stock hurst shifter in that car at 8k rpm are hardly a miss..
Assuming that all of that checks out and is in good working order, you may can then attempt to adjust your clutch linkage. Especially if you are getting a grinding action in reverse. (unsynchronized).
NOW, if you have gone through these checks and everything else above is fine, but are still getting the grinding, then your fourth gear synchronizer is going out or your fork and clutch hub are worn out which means you have to pull the tranny and rebuild it. Make sure you use the torque lock sliders and new forks if you get to this point.
Let us know how it turns out and what fixes the problem..
Tony
After each one of these checks take a test drive.
First things first, check the cotton pickin oil!! Its a plug on the passenger side, crack it loose and oil should run out. If not, fill it until it does with some 75 weight gear oil.
If its a factory shifter check the holes in the levers to make sure they are not oblong and check the actual linkage arms to make sure they are not worn down. If they aren't adjust linkage according to chassis service manual.
These parts get worked millions of times throughout a vehicles life, and they are subject to wear and replacement as is anything else.
If you have a hurst shifter and you used the plastic bushings, order the hurst pit pack. Adjust linkage with a 1/4 -20 bolt four inches long. That plastic pin has too much slop for me...
Summit Racing Part Number:
HUU-3327302
Those are metal bushings that are not subject to much wear. I do grease em once a year. (They are in my Z28 and THAT linkage adjusted properly with the bolt hasn't exactly seen an easy life with me.) But my throws on the stock hurst shifter in that car at 8k rpm are hardly a miss..
Assuming that all of that checks out and is in good working order, you may can then attempt to adjust your clutch linkage. Especially if you are getting a grinding action in reverse. (unsynchronized).
NOW, if you have gone through these checks and everything else above is fine, but are still getting the grinding, then your fourth gear synchronizer is going out or your fork and clutch hub are worn out which means you have to pull the tranny and rebuild it. Make sure you use the torque lock sliders and new forks if you get to this point.
Let us know how it turns out and what fixes the problem..
Tony
Freddie