Question For the Differential Experts
Thread Starter
Safety Car
Joined: Aug 2001
Posts: 4,883
Likes: 11
From: North Easton Mass
Question For the Differential Experts
When I removed the wheels to dismantle the frame of the 72 I noticed that the yolk on the drivers' side extended out 3/8" or so. the yolk on the passenger side stayed in place in the differential after the halfshafts were removed but the drivers' side moved freely. I thought at first that the C-clip had come off the yolk but after opening up the differential and removing the yolk this is what I found:
It's clear that there is no provision for a C-clip on the yolk. Is that normal or has the yolk been replaced at some point? Should there be a C-clip on both yolks? The differential on my 79 had yolks that were not removeable from the case.
I should mention that it is obvious that someone had been inside the diff at some point. There were marks that looked like a screwdriver had been used to separate the gears and I'm pretty sure that silicon sealer didn't exist in 1972.
Rick B.
It's clear that there is no provision for a C-clip on the yolk. Is that normal or has the yolk been replaced at some point? Should there be a C-clip on both yolks? The differential on my 79 had yolks that were not removeable from the case.
I should mention that it is obvious that someone had been inside the diff at some point. There were marks that looked like a screwdriver had been used to separate the gears and I'm pretty sure that silicon sealer didn't exist in 1972.
Rick B.
Le Mans Master
Joined: Jul 2005
Posts: 5,752
Likes: 4
From: Austin Texas
You can see the remains of the snap ring groove. The yoke has worn down so far as to remove the other side of the retaining splined area. Try to find the snap rings and get some new side yokes.
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
It would be wise to disassemble the diff and rebuild. Just think of all that metal inside grinding away at your bearings and such. This is normal high mileage wear. Rebuild or you will be rebuilding shortly.
Thread Starter
Safety Car
Joined: Aug 2001
Posts: 4,883
Likes: 11
From: North Easton Mass
I had read in other posts about wear on the yolks but here is what the inside of the diff looks like when both yolks are inserted:
I was looking for the C-clip or debris but I didn't find anything inside of the case.
Both of the yolks seem to come to about the same distance from the center pin.
Bottom line is I'm trying to avoid a differential rebuild right now if possible. I'd rather blow it up after I get the LS1 installed.
Rick B.
I was looking for the C-clip or debris but I didn't find anything inside of the case.
Both of the yolks seem to come to about the same distance from the center pin.
Bottom line is I'm trying to avoid a differential rebuild right now if possible. I'd rather blow it up after I get the LS1 installed.
Rick B.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Clean the case out good, Buy 2 new yokes, c clips and seals and slap it back together. Fill with lube and a bottle of posi additive and put it back in. But you will probably be back in there soon!
Tech Contributor
Joined: Aug 1999
Posts: 15,166
Likes: 3,968
From: Connecticut, USA
First thing I'd do is look it over good if bubba has been in there and it looks like that might be the case. It appears that yoke still has the chamfer on it which is the end of the yoke. If it fits close to the pin then I would say it is a rebuild yoke that the snap ring groove was not machined in- it should not have been used if that is the case. I can't clearly see the pinion pattern so can't say if the pinion is off- if it was then the diff would have been howling or hitting the case and you would see marks on it.
As said if it were me or a friends I would rebuild it, be done with it and get on to finishing the car. Your call and a custom job runs well over $1k. I would at least replace the yokes and yoke seals.
Here are some pictures for you.
This is a diff I did that had worn yokes. The RH one is pointed out.
I had to grind off the end to remove it because it was so mushroomed.
Here is the finished job with new yokes I fit to .005 endplay.
As said if it were me or a friends I would rebuild it, be done with it and get on to finishing the car. Your call and a custom job runs well over $1k. I would at least replace the yokes and yoke seals.
Here are some pictures for you.
This is a diff I did that had worn yokes. The RH one is pointed out.
I had to grind off the end to remove it because it was so mushroomed.
Here is the finished job with new yokes I fit to .005 endplay.
Last edited by GTR1999; Jan 13, 2007 at 11:38 AM.
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Brett Foote
Melting Slicks
Joined: Feb 2001
Posts: 3,330
Likes: 13
From: Europe , Luxembourg
Hi
If it's not a daily driver and you don't want to spend money, you could get a mashine shop to cut a groove in it and it could be reused.
It was somehow OK without a snap ring and surely is like perfect with one.
The other one still looks to be within limits as is.
Günther
If it's not a daily driver and you don't want to spend money, you could get a mashine shop to cut a groove in it and it could be reused.
It was somehow OK without a snap ring and surely is like perfect with one.
The other one still looks to be within limits as is.
Günther
NCM Grand Opening Veteran
Joined: Sep 2005
Posts: 20,979
Likes: 384
From: South of giving a damn
St. Jude Donor '11, '17
I agree with GTR1999. You obviously have the whole rear end disassembled, so why button it back up & then redo it later. Seems like extra aggravation to me. I'd bite the bullet & swap differentials at the least. Of course this is only as good as the person doing the rebuild. Why not have a custom job from someone like GTR1999? You'd never have to worry about the differential again.
Thread Starter
Safety Car
Joined: Aug 2001
Posts: 4,883
Likes: 11
From: North Easton Mass
First thing I'd do is look it over good if bubba has been in there and it looks like that might be the case. It appears that yoke still has the chamfer on it which is the end of the yoke. If it fits close to the pin then I would say it is a rebuild yoke that the snap ring groove was not machined in- it should not have been used if that is the case. I can't clearly see the pinion pattern so can't say if the pinion is off- if it was then the diff would have been howling or hitting the case and you would see marks on it.
As said if it were me or a friends I would rebuild it, be done with it and get on to finishing the car. Your call and a custom job runs well over $1k. I would at least replace the yokes and yoke seals.
As said if it were me or a friends I would rebuild it, be done with it and get on to finishing the car. Your call and a custom job runs well over $1k. I would at least replace the yokes and yoke seals.
Gary,
Thanks for posting the pics. I certainly looked like someone had been in the diff before - I saw at least 1 screwdriver mark where the ring gear had been removed. I wasn't hearing any noise from the diff when we drove the car this summer, but we didn't put mch mileage on it and it never got up to highway speed. I know a rebuild is the best thing to do, especially since the LS1 is going to be twisting the diff a lot harder than the original motor ever did. It's a matter of $ at this point.
Here are a couple pics of the ring gear. I did find 1 chipped tooth - don't know how serious that is, but I'd be interested to know if you thing the ring gear looks excessively worn. Thanks.
Rick B.
