# Differential Question



## sbagley50 (Nov 30, 2009)

I'm putting a 65 GTO rear end in my 64. It has casting #9779822. I was planning to transplant the axles from the old rear end, which I think was from a 64 lemans. It's casting # is 9773369. I'm not sure this is the rear end I rat-holed. Can anyone tell me if the 9773369 came from a 64?
Anyway, the axles don't seem to fit. They look the same, an have castings 793 on the hub part.
I'd appreciate any help with what I have.
Steve. [email protected]


----------



## Too Many Projects (Nov 15, 2008)

Steve, I'll see if i can get a mod to move this to the "technical" forum for an answer.


----------



## Rukee (Feb 8, 2007)

What part of the axles don't fit if they are the same part #?


----------



## VettenGoat (Jun 19, 2007)

Aside from the upper control arms, the 65 rear (979822) will fit the 64. Width is the same, and hence the axles will be the same.....IF they're from another limited slip rear. If the axles you have are out of a 64 LeMans, they may be out of an open end rear hence the no-fit. 

Mike


----------



## 66tempestGT (Nov 28, 2009)

whats different about the uppers? what would be different from a pos to an open diff?


----------



## geeteeohguy (Feb 2, 2008)

The '65 rear should go right into the '64, upper arms and all.


----------



## Rukee (Feb 8, 2007)

66tempestGT said:


> what would be different from a pos to an open diff?


I may be wrong on this, but isn't the posi axle held in with a bolt on axle flange and the open axle shaft held in with a 'C' clip?


----------



## Too Many Projects (Nov 15, 2008)

66tempestGT said:


> what would be different from a pos to an open diff?


Only the ring carrier inside. Everything else is the same. The axles on a Pontiac are retained with an outer bearing retainer that bolts to the axle tube. The c-clip axles are a Chevrolet deal.


----------



## 66tempestGT (Nov 28, 2009)

if that is the case you wouldnt be able to replace an open diff with a pos unit without also replacing the axles. i am familiar with chevys but not the pontiac specific rears.


----------



## geeteeohguy (Feb 2, 2008)

Pontiac diffs don't have c-clips. You can replace and open carrier with a safe-t-track carrier if it's the same series of carrier. Axles are the same with the same type of rear (10 bolt, etc.)


----------



## fheckro (Nov 19, 2009)

when did GM first start making C-clip axles? I thought they were a 70's thing?? All I know about them is to avoid em.


----------



## Too Many Projects (Nov 15, 2008)

I know they date back to '64 but beyond that I have no experience.


----------

