Differential Questions
Thread Starter
Intermediate
Joined: Aug 2007
Posts: 28
Likes: 0
From: Everett Wa
Differential Questions
I had to open my differential up to replace the C-clip on one of the side yokes which seems to have either vanished or was never there when i bought the car. I do not really want to disassemble the diff.
My question is, what can i /should I replace on the differential without actually taking it apart, so as to avoid having to set it up again.
I was thinking the seals, but can i do bearings as well, or does that require disassembly. How does a person get the seals out? Just pry with something?
Most info i found assumed a complete rebuild..
My question is, what can i /should I replace on the differential without actually taking it apart, so as to avoid having to set it up again.
I was thinking the seals, but can i do bearings as well, or does that require disassembly. How does a person get the seals out? Just pry with something?
Most info i found assumed a complete rebuild..
Instructor
Joined: Apr 2005
Posts: 141
Likes: 0
From: Downers Grove IL
2 Ideas, one get a copy of the GM manual, and two talk to Doc Rebuild at the following. http://www.docrebuild.com Just put in new seals in a 75 rear end and his advice saved the day.
Good luck Polo
Good luck Polo
Thread Starter
Intermediate
Joined: Aug 2007
Posts: 28
Likes: 0
From: Everett Wa
OK, thanks, looks like it's just going to be the side yoke seals. Now i just need to figure out how to remove the c-clip holding in the remaining yoke. It seems to be rotated around in there so the opening in the clip is not visible.
Racer
Joined: Apr 2008
Posts: 254
Likes: 5
From: ingleside illinois
Remove the center pin-i bet your side yokes are mushroomed at the end.If so i would replace them or it wont be long before you have to do this again.You might have to beat out the yokes with a hammer.If you dont replace yoke when reinstalling check end play should be 20-35 max.I'll bet your a 100 or more.Make sure you clean everything out and put in posi additive.Trust me you dont want to do this twice.
Thread Starter
Intermediate
Joined: Aug 2007
Posts: 28
Likes: 0
From: Everett Wa
Thanks, Not sure i would have figured that one out any time soon 
(as you can probably guess, i don't know much about differentials)
I took some measurements before removing the remaining yoke. The end play is ~.038-.040, the distance from the clip groove to the flat part on the end is .170-.175 on both. It's hard to get an accurate measurement. Also both yokes are able to freely slide in and out of the differential. I did not have to force it out at all.
I did not get measurements on the end play on the other once since that would require installing it back in with a new c-clip.
Based on all that, can I just put it all back together and leave the existing yokes in there?
I am hoping that removing that pin does not mean i cant just put it back together and call it good. Do i need to do anything special to put it back or can i just slide it back in and put the bolt back in to hold it?
Here are some bad pictures.
http://home.comcast.net/~bmanops/Photos/100_1929.jpg
http://home.comcast.net/~bmanops/Photos/100_1932.jpg
(as you can probably guess, i don't know much about differentials)I took some measurements before removing the remaining yoke. The end play is ~.038-.040, the distance from the clip groove to the flat part on the end is .170-.175 on both. It's hard to get an accurate measurement. Also both yokes are able to freely slide in and out of the differential. I did not have to force it out at all.
I did not get measurements on the end play on the other once since that would require installing it back in with a new c-clip.
Based on all that, can I just put it all back together and leave the existing yokes in there?
I am hoping that removing that pin does not mean i cant just put it back together and call it good. Do i need to do anything special to put it back or can i just slide it back in and put the bolt back in to hold it?
Here are some bad pictures.
http://home.comcast.net/~bmanops/Photos/100_1929.jpg
http://home.comcast.net/~bmanops/Photos/100_1932.jpg
Racer
Joined: Apr 2008
Posts: 254
Likes: 5
From: ingleside illinois
You can just slide it back in and put the bolt in and your done.But 1st were the hell did the c clip go -no metal was in the fluid.How long have you been driving the car that way.Usuall anything over .35 endplay is a sign of worn yokes.Your on the limit-i bet when you put the other on in its alot looser than the other if it is change the thing-or both dont do this twice.
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Tech Contributor
Joined: Aug 1999
Posts: 15,114
Likes: 3,905
From: Connecticut, USA
038-040 endplay without any other issues isn't too bad. Replacing them with rebuilt yokes will only gain you about 010" Depending on the year of the car the yoke case hardening may be mininum if at all. Typically they should be hardened about 030" deep, given yours are worn about 015-020" you may be near the limit.This really applys to the 63-73's about 74-75 they started to have issues.
Thread Starter
Intermediate
Joined: Aug 2007
Posts: 28
Likes: 0
From: Everett Wa
I have never had the pleasure of driving the car 
I bought it as a project car someone one gave up on after they had completely stripped out the interior and partly disassembled everything else. I have no idea how long he had driven it like that. I've looked all over inside and cant spot it anywhere in there. I also checked the stuff i was wiping out the bottom to clean it out a bit, and didn't find any sign of metal in that. I suspect that it may have been taken apart before. One of the half shafts had different u joints than the other one, and the one also had less rust on the u-bolts.
Do reconditioned yokes have new hardening on the ends? Or does a person need to buy new yokes to gain back the .030 of hardening.
BTW. The car is a '77
What amount of use/Engine would justify upgrading to HD straps?
Thanks
I bought it as a project car someone one gave up on after they had completely stripped out the interior and partly disassembled everything else. I have no idea how long he had driven it like that. I've looked all over inside and cant spot it anywhere in there. I also checked the stuff i was wiping out the bottom to clean it out a bit, and didn't find any sign of metal in that. I suspect that it may have been taken apart before. One of the half shafts had different u joints than the other one, and the one also had less rust on the u-bolts.Do reconditioned yokes have new hardening on the ends? Or does a person need to buy new yokes to gain back the .030 of hardening.
BTW. The car is a '77
What amount of use/Engine would justify upgrading to HD straps?
Thanks
Tech Contributor
Joined: Aug 1999
Posts: 15,114
Likes: 3,905
From: Connecticut, USA
Don't feel bad, most C3's on the market need work. Buying a turn key car will cost $25k+
77's had poor yokes, poor posi clutches,poor RG bolts, but good posi cases and spiders.
Just about everyone uses Lonestar rebuilt yokes with hardened tips. They are fine. In fact when I tune a posi I still have to grind them to fit for the 005-010 endplay I set them to. You will not achieve this endplay by replacing the yokes alone.
HD yokes were used on base eng automatics and L82's in the later C3's, BB's used them as well. If you have a base 4 spd car then you have the U bolt yokes. They are fine unless you plan on launching the car or just want the added strength. If you switch you'll need the caps and they are out of control on cost, about $40 a cap for used GM. I haven't seen a good aftermarket set yet but you should check the fit for correct crush regardless. If you're building a 300-400 hp car the U bolt yokes should be fine, I'd be more concerned with the ujoints. Use Spicer solids.
77's had poor yokes, poor posi clutches,poor RG bolts, but good posi cases and spiders.
Just about everyone uses Lonestar rebuilt yokes with hardened tips. They are fine. In fact when I tune a posi I still have to grind them to fit for the 005-010 endplay I set them to. You will not achieve this endplay by replacing the yokes alone.
HD yokes were used on base eng automatics and L82's in the later C3's, BB's used them as well. If you have a base 4 spd car then you have the U bolt yokes. They are fine unless you plan on launching the car or just want the added strength. If you switch you'll need the caps and they are out of control on cost, about $40 a cap for used GM. I haven't seen a good aftermarket set yet but you should check the fit for correct crush regardless. If you're building a 300-400 hp car the U bolt yokes should be fine, I'd be more concerned with the ujoints. Use Spicer solids.
Safety Car
Joined: Oct 2006
Posts: 3,930
Likes: 15
From: Calgary Alberta
