67 rear to 64 rear

[Rex T.]

Is it possible to install the carrier assembly and gears from a 1972 rear end into a 63 or 64 rear end case? Thanks, Rex #8089

[Joe L.]

Re: 67 rear to 64 rear

Rex------

It is possible to do the converse. That is, install 63-64 gears in 1965 or later case. However, I don't think that you can install the later gear set in the earlier case. I'm not 100% sure about this, though.

[Chris D.]

Re: 67 rear to 64 rear

Rex,

Yes, you can. I bolted my original 63 ring gear to a later model carrier when I decided to add positraction. Got tired of spining the inside tire.

[Joe L.]

Re: 67 rear to 64 rear

Chris-----

Are you talking about the positraction case or the differential case (i.e "pumpkin")? You can use the later style posi case with 63-64 innerds. It's using the later innerds in a 63-64 "pumpkin" that I'm not sure can be done.

[Chris D.]

Re: 67 rear to 64 rear

Joe,

Sorry for the mixup. I just have to get used to the fact that I will NEVER be able to apply the terms "case" and "carrier" as GM intended. My mind can't hold onto the idea of a case on the inside. Allow me to restate:

I bolted my original '63 ring gear to a later model posi case (innerds) and then installed the assembly into the original '63 carrier (as in pumpkin, outer casting that mounts the bearings, contains the fluid, and is visible from underneath the car). Knowing that the 63 posi was weak and rare even 15 years ago, it seemed the best way to go. Since the carrier and gears share a service application range from '63 to '79 and I might have figured it out. Or more likely someone in the club coached me back then but details are getting dimmer all the time.

Chris

[Chris D.]

Re: 67 rear to 64 rear

Joe,

Reading your question again, if I re-interpret it to mean swapping the smaller differential gears, side gears, and clutch packs, between different year posi cases, then my earlier responses do not apply to your question. I didn't do that. I updated the entire subassembly.

But I suspect Rex's original question suffered from my same case vs. carrier dyslexia. I read his question to be, "Is it possible to install the (posi) "case" assembly and gears from a 1972 rear end into a 63 or 64 rear end "carrier"?"

[Rex T.]

Re: 67 rear to 64 rear

Whew!!!!!!!!!!!!! Is anybody as confused as me?????? I hope not, but many thanks to all for your input. Perhaps I did not ask the question correctly. I have a 1972 dated rear end housing (contains 4.11 gear w/posi), the housing that the leaf spring bolts to, in my 64. I have the correct dated rear end housing (the part that has the cover that bolts onto it) and would like to transfer all the guts (complete assembly - carrier with ring & pinion and posi unit) into the 64 housing. It sounds like this may be possible, but before I remove it from the car, I would like to have confirmation from someone who has done it. Thanks for your help. Rex

[Chris D.]

Re: 67 rear to 64 rear

Rex,

Sorry for the confusion.

So what you want is to keep everything from the '72 rear currently on the car EXCEPT change to the original 64 external housing. (Carrier in GM-speak but lets not start that again).

The parts you want to install, as a complete set, will fit into the '64 housing. Both ring and pinion will need to be reshimmed to establish proper backlash and mesh pattern.

From a more recent disscusion on the board, your original U-joint flange has a different spline count than the '72 pinion gear. Since you are starting with the '72 assembly already in the car, this must have been updated previously. So you are set.

[Rex T.]

Re: 67 rear to 64 rear

Thanks everyone for your help. Sorry if I confused anyone with my question. Thanks again for your help.
Rex