Extesion seal
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Extesion seal
Hello, I have a 76 that has had a complete frame off including floor pans. Car is in great shape except I am getting a leak around the yoke at the tranny. I replaced the seal when I had the car apart and had a buddy of mine replce it (who owns a tranny shop) it again not long ago. it was good for a few days and then leaked again. He said the yoke looked good and he even cleaned it - but maybe it should be replaced...is there not some kind of an extension seal that is wider that can be used?? this would move the seal to a new part of the yolk and prevent leaking...Diff and everything down lower are good. nothing loose etc....Thanks!
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I am not sure but we all seem to think it is between lip and yoke..not sure how I would fix the latter...I would dive into a new yoke if the old one did not look so good.... I realize it could be worn and not visible. There must be a seal kit I can try.
Le Mans Master
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From: mount holly NC
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If it's not leaking past the seal, oil could be wicking up between the flange and the pinion, apply some sealant on the splines.
Burning Brakes
Joined: Dec 2010
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From: Winston Salem NC
Is it the original yoke? It could be that wear has cut a groove in it and the seal can't meet it all the way around the diameter.
I don't think the yoke moves in and out very much so the seal just wears and wears on the yoke.
Please correct me if I'm wrong.
I don't think the yoke moves in and out very much so the seal just wears and wears on the yoke.
Please correct me if I'm wrong.
Le Mans Master
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From: Gladstone MO
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Automatic? Manual?
Automatics, fluid can seep thru the splines and come out the vent in the center cap in the yoke. A coat of heavy grease will stop it for a while, but the end result makes more of a mess than the ATF. You can RTV (or weld up) the little hole in the cap (after cleaning). The driveshaft/yoke have very little movement on a Corvette and will cause no problems. On other cars, the yoke slides in and out, moving with the rear axle over bumps. Corvettes do not. I'd suggest that someplace the yoke got replaced for some reason with one that was vented.
Manual, at least on my 69, the yoke has no cap and is totally open in the center. Never noticed any drips or marks on the bottom of the car, but the splines do stay wet.
Automatics, fluid can seep thru the splines and come out the vent in the center cap in the yoke. A coat of heavy grease will stop it for a while, but the end result makes more of a mess than the ATF. You can RTV (or weld up) the little hole in the cap (after cleaning). The driveshaft/yoke have very little movement on a Corvette and will cause no problems. On other cars, the yoke slides in and out, moving with the rear axle over bumps. Corvettes do not. I'd suggest that someplace the yoke got replaced for some reason with one that was vented.
Manual, at least on my 69, the yoke has no cap and is totally open in the center. Never noticed any drips or marks on the bottom of the car, but the splines do stay wet.
Team Owner
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From: Crossville TN
There is a bushing on that rear output shaft for the transmission. If that bushing is worn, you can replace the seal but it won't last long...too much wobble in the shaft. Grab the driveshaft near the tranny output and try to move it up/down and side-to-side. If it has more than a very slight wiggle, the bushing is worn. If your tranny has a rear output housing, you can remove the driveshaft and that housing and replace the bushing AND the seal.
Also, make sure that you can polish up the seal lip wear area on the driveshaft yoke. If it is badly worn, drive the new seal in to a different depth so that it runs in a different spot on the yoke.
Also, make sure that you can polish up the seal lip wear area on the driveshaft yoke. If it is badly worn, drive the new seal in to a different depth so that it runs in a different spot on the yoke.
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There is a bushing on that rear output shaft for the transmission. If that bushing is worn, you can replace the seal. but it won't last long...too much wobble in the shaft. Grab the driveshaft near the tranny output and try to move it up/down and side-to-side. If it has more than a very slight wiggle, the bushing is worn. If your tranny has a rear output housing, you can remove the driveshaft and that housing and replace the bushing AND the seal.
Also, make sure that you can polish up the seal lip wear area on the driveshaft yoke. If it is badly worn, drive the new seal in to a different depth so that it runs in a different spot on the yoke.
Also, make sure that you can polish up the seal lip wear area on the driveshaft yoke. If it is badly worn, drive the new seal in to a different depth so that it runs in a different spot on the yoke.
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Safety Car
Joined: Jan 2009
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From: New York
Pull the tail housing and put a new bushing in 7T1vette is right .. It is not a matter of feeling a wiggle the bushing can were several thousands and that allows oil to build up behind the seal and leak.
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sooo the bushing that is behind the seal inside the housing? not being a wise guy - just looking for clarification. Won't all the tranny flluid come out? Funny, I replaced every seal I could find on that tranny when I had it out! whats the saying>>if it does not leak, its empty!
Safety Car
Joined: Jan 2009
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From: New York
Yes you will lose some fluid , but fix the problem. Front and rear seals leak because the bushings have worn down .. The seal does provide a seal , but very little oil runs against them with the proper bushing clearance.
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I can't picture the inner seal but i am sure I will see it once in there. So I should re do both seals correct? I am gonna take a stab at in now before something else gets in the way (cleaning house etc)
Safety Car
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From: New York
Not sure what you mean both seals , the case seal will be a o ring when you pull off the tail housing .. Same for speedo assembly ,, the tail shaft you know is steel encased.
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There is a bushing on that rear output shaft for the transmission. If that bushing is worn, you can replace the seal but it won't last long...too much wobble in the shaft. Grab the driveshaft near the tranny output and try to move it up/down and side-to-side. If it has more than a very slight wiggle, the bushing is worn. If your tranny has a rear output housing, you can remove the driveshaft and that housing and replace the bushing AND the seal.
Also, make sure that you can polish up the seal lip wear area on the driveshaft yoke. If it is badly worn, drive the new seal in to a different depth so that it runs in a different spot on the yoke.
Also, make sure that you can polish up the seal lip wear area on the driveshaft yoke. If it is badly worn, drive the new seal in to a different depth so that it runs in a different spot on the yoke.
Drifting
Joined: Oct 2000
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From: Shawano WI
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There is a kit that you can buy that has a sleeve and a new seal. About $40.00...the sleave goes over the old yoke and provides a new surface. I wonder if its worth trying. yoke has no visible wear. I may just rplace the yoke, seal, and this bushing you guys are talking about. I just need clarification on what this bushing is.. when I was at the auto parts store yesterday (not autozone) they where not sure what or where the bushing is
Drifting
Joined: Oct 2000
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From: Shawano WI
#17 is the seal
#16 is the bushing
If you have a Turbo 350 trans the bushing part # is ATP brand SB25
If you have a Turbo 400 trans the bushing part # is ATP brand JB54
If your parts house doesn't have ATP brand they should be able to cross them over. Bushing is around $4.00 to $6.00.
As far as the sleeve for the yolk, I would have the yolk mic'd first to see if there is any wear before I used a sleeve.
#16 is the bushing
If you have a Turbo 350 trans the bushing part # is ATP brand SB25
If you have a Turbo 400 trans the bushing part # is ATP brand JB54
If your parts house doesn't have ATP brand they should be able to cross them over. Bushing is around $4.00 to $6.00.
As far as the sleeve for the yolk, I would have the yolk mic'd first to see if there is any wear before I used a sleeve.
Last edited by Pete79L82; Feb 23, 2014 at 09:49 AM.