[C2] Differential
Thread Starter
Pro
Joined: Jan 2005
Posts: 686
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From: San Jose Ca
Differential
Hy guys. I've got my dads '64, which he bought new and raced in SCCA B production in the mid to late '60s. (Got a previous thread about 17" Torq Thrusts going too). Anyway, there's a TON of play in the axle stub shafts, and the posi is barely doing anything, practically an open diff at this point. I assume the worn posi has something to do with the loose stub shafts. Now assuming it's actually a '64 diff, it seems nobody will touch them because of parts availability. No worries, it's not a numbers matching car, and I'd prefer 3.55 over the current 3.70 anyway. So my question is, what years will interchange, including the much more available C3 diffs? I see vague mention of different yokes in various years, but nothing concrete. Any help would be appreciated!
Thanks
Scott
Thanks
Scott
Tech Contributor
Joined: Aug 1999
Posts: 15,166
Likes: 3,968
From: Connecticut, USA
They can be rebuilt. The posi's were DANA and junk. The ring and pinion were junk. However, the housing and axles should be good. Now excessive axle endplay may be the axles but original 64's were pretty good, maybe your Dad had some work done to it years ago, especially if it was raced.
I would remove it and pull the cover to see just what you got. They all had issues so don't expect to get someone's used diff and bolt it in without checking it. Any 63-79 will bolt into your car. You will need to get the better 69-79 front bracket. If you look for a used diff look for 72-79 but the other years will fit, they had weaker posi's in them.
If you have any questions just let me know.
I would remove it and pull the cover to see just what you got. They all had issues so don't expect to get someone's used diff and bolt it in without checking it. Any 63-79 will bolt into your car. You will need to get the better 69-79 front bracket. If you look for a used diff look for 72-79 but the other years will fit, they had weaker posi's in them.
If you have any questions just let me know.
Thread Starter
Pro
Joined: Jan 2005
Posts: 686
Likes: 62
From: San Jose Ca
They can be rebuilt. The posi's were DANA and junk. The ring and pinion were junk. However, the housing and axles should be good. Now excessive axle endplay may be the axles but original 64's were pretty good, maybe your Dad had some work done to it years ago, especially if it was raced.
I would remove it and pull the cover to see just what you got. They all had issues so don't expect to get someone's used diff and bolt it in without checking it. Any 63-79 will bolt into your car. You will need to get the better 69-79 front bracket. If you look for a used diff look for 72-79 but the other years will fit, they had weaker posi's in them.
If you have any questions just let me know.
I would remove it and pull the cover to see just what you got. They all had issues so don't expect to get someone's used diff and bolt it in without checking it. Any 63-79 will bolt into your car. You will need to get the better 69-79 front bracket. If you look for a used diff look for 72-79 but the other years will fit, they had weaker posi's in them.
If you have any questions just let me know.
BTW, am I correct in thinking that a worn posi would create excessive axle play as I assume the side gears sink further into the carrier as the clutches wear?
Scott
Last edited by MaxLean; May 31, 2022 at 04:31 PM.
Tech Contributor
Joined: Aug 1999
Posts: 15,166
Likes: 3,968
From: Connecticut, USA
Scott,
I would be surprised if it's still the 64 but you never know. You can look at the lower LH corner of the diff for the casting date and the stamping on the bottom. However, it can still be a 64 housing with new internals. The only way you're going to know is to remove the diff and pull the cover for a look. send me some pictures if you do and I can tell you what I see.
I would be surprised if it's still the 64 but you never know. You can look at the lower LH corner of the diff for the casting date and the stamping on the bottom. However, it can still be a 64 housing with new internals. The only way you're going to know is to remove the diff and pull the cover for a look. send me some pictures if you do and I can tell you what I see.
Thread Starter
Pro
Joined: Jan 2005
Posts: 686
Likes: 62
From: San Jose Ca
Scott,
I would be surprised if it's still the 64 but you never know. You can look at the lower LH corner of the diff for the casting date and the stamping on the bottom. However, it can still be a 64 housing with new internals. The only way you're going to know is to remove the diff and pull the cover for a look. send me some pictures if you do and I can tell you what I see.
I would be surprised if it's still the 64 but you never know. You can look at the lower LH corner of the diff for the casting date and the stamping on the bottom. However, it can still be a 64 housing with new internals. The only way you're going to know is to remove the diff and pull the cover for a look. send me some pictures if you do and I can tell you what I see.
Scott
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GTR1999, I was told that the 70's side shaft were not properly hardened on the ends, is this true? These shaft tell me it was true.
Joe
Tech Contributor
Joined: Aug 1999
Posts: 15,166
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From: Connecticut, USA
It's true, original 70-79's were lightly case hardened and by 50k miles it was gone. The earlier ones are a little better but by 74 they were poorly hardened. By the time they wear to the snap ring you have to watch that the axle doesn't crash and grind into the housing.
The 63 to 69's were much better, some have worn but not as bad as the 70's. I have rebuilt original c2 diffs with over 100k miles and still had to fit the original axles to the tuned posi's I built.
The 63 to 69's were much better, some have worn but not as bad as the 70's. I have rebuilt original c2 diffs with over 100k miles and still had to fit the original axles to the tuned posi's I built.
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Tech Contributor
Joined: Aug 1999
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From: Connecticut, USA
Axle end play comes from poor posi setup, worn axles, worn posi cross shaft holes. Stock built posi's, new loaded posi's are not the best.