C2 Differential issue
Le Mans Master
Joined: Feb 2008
Posts: 6,505
Likes: 1,926
From: Folsom CA
Clean off all the high spots, fill any low spots or dents with "The Right Stuff". put a thin coat of The Right Stuff around the Seal OD and install. Let it sit for 24 hours and add oil. Should hold for many years.
Ths assumes the factory seal has a lip on it that stops the seal from going deep into that housing. If the seal does not have a lip you could drive it deep enough to seal on a good surface. Make sure the housing is clean of any high spots that would damage the seal and the axle stub it polished smooth for the seal to ride in a slightly deeper position.
I am sure there is talent out there that might be able to Cast Iron weld the housing and build up the metal and re cut the housing bore to factory specs but that would be a lot. of money and down time. There are companies/people that can cold weld to build up the cast iren without distortion. Not sure you need that to seal the axle.
Ths assumes the factory seal has a lip on it that stops the seal from going deep into that housing. If the seal does not have a lip you could drive it deep enough to seal on a good surface. Make sure the housing is clean of any high spots that would damage the seal and the axle stub it polished smooth for the seal to ride in a slightly deeper position.
I am sure there is talent out there that might be able to Cast Iron weld the housing and build up the metal and re cut the housing bore to factory specs but that would be a lot. of money and down time. There are companies/people that can cold weld to build up the cast iren without distortion. Not sure you need that to seal the axle.
Tech Contributor
Joined: Aug 1999
Posts: 15,176
Likes: 3,990
From: Connecticut, USA
You don't have to do anything to it. There is still more than enough of the bore left to support the seal. Many C3 housings are worn down more than this from bad axles. Put sealant on the seal OD and tap it in.
That appears to be a 65 housing- 9/17/1965, used in a 66. More of a concern is using the correct case shims to get the correct preloads. Also 66 posi cases were very prone to cracking, so much so they were revised later on. Check the posi close. Check the ring gear holes, check the axles, and check the cap fit. I am building a 64 diff now used in a 65, the posi case was cracked, the gears NG, the rear cover cracked from using the wrong spring pad bolts.
Good luck.
That appears to be a 65 housing- 9/17/1965, used in a 66. More of a concern is using the correct case shims to get the correct preloads. Also 66 posi cases were very prone to cracking, so much so they were revised later on. Check the posi close. Check the ring gear holes, check the axles, and check the cap fit. I am building a 64 diff now used in a 65, the posi case was cracked, the gears NG, the rear cover cracked from using the wrong spring pad bolts.
Good luck.
Last edited by GTR1999; May 27, 2026 at 09:05 PM.
Drifting
Joined: Aug 2021
Posts: 1,402
Likes: 996
From: Sacramento, Ca
I don't know if it's just an optical illusion or not, but it appears that there are a few spots where the metal has been deformed into the bore for the seal. If so, those areas would have to be cleaned up before you would be able to just press in a new seal.
Ted
Ted
Tech Contributor
Joined: Aug 1999
Posts: 15,176
Likes: 3,990
From: Connecticut, USA
Correct, a slight touch with a small grinder at those lead in points will prevent distortion and allow the seal to seat correctly
