64 Differential

[Michael C.]

In my search to find someone reputable to rebuild the differential on my 64 I'm only finding shops that rebuild rear ends on 65 and up. These shops say that differential parts for 63-64 are impossible to get. Has anyone else came across this situation?

[James W.]

Re: 64 Differential

Michael,

I think if you give Bairs a call they will in fact rebuild your '64 differential. I called to inquire about this a year or so ago and they said that they could/would do the work. I think the big difference is that at sometime between 1963 and 1964 the pinion spline count or something related to the pinion changed to what the 1965 and up cars have.

Good Luck,

James West

[Harry S.]

Re: 64 Differential

Also, the 63/64 came with the Dana posi. unit. As I recall this unit was prone to failure under regular driving conditions. I believe there was a recall to replace the Dana units with Eaton units, a better unit. The Eaton unit and the internal characteristics of the 65 and up carrier was changed. So to put an Eaton unit in a 63/64 carrier the shims must be machined to fit properly.

All of this can be done, but some of the shops just don't want to deal with the extra work. Additionally if your carrier still has the Dana unit, parts are next to impossible to find. I have an Eaton in my 63 carrier and a broken Dana sitting in a box.

Here is a picture!

[Mike M.]

Re: 64 Differential

Bairs will do your differential. They did a 63 for me about 2 years ago.

[Paul J.]

Re: 64 Differential

What about our friend and fellow poster Gary Ramadei? Will he work on 63-64 diffs?

[Duke W.]

Re: 64 Differential

Also, the 63/64 came with the Dana posi. unit. As I recall this unit was prone to failure under regular driving conditions. I believe there was a recall to replace the Dana units with Eaton units, a better unit. The Eaton unit and the internal characteristics of the 65 and up carrier was changed. So to put an Eaton unit in a 63/64 carrier the shims must be machined to fit properly.

All of this can be done, but some of the shops just don't want to deal with the extra work. Additionally if your carrier still has the Dana unit, parts are next to impossible to find. I have an Eaton in my 63 carrier and a broken Dana sitting in a box.

Here is a picture!

I believe the early Positraction unit - the one illustrated in the 1963 Corvette Shop Manual - is a Borg-Warner. I don't remember any "recall", but when I opened up my '63 axle in the seventies for an overhaul it had an Eaton. It may have been installed when the axle was out to replace a broken drive pinion in 1966, but it wasn't on the RO. The later Eaton unit fits, and I didn't have to machine any shims. The Eaton is the service assembly for '63/'64 axles.

So I now have a '63/'64 R&P along with the proper companion flange and a later Eaton Positraction unit. The '63/'64 carrier will also accept the later R&P, but this also requires the later companion flange due to the different spline count between the '63/'64 and later drive pinions.

Duke

[Gary R.]

Re: 64 Differential

Hi Paul,
Yes I do 63-79 diff's.
Here's the deal with 63-64's. As I'm sure most know posi was an option but most had it. The 63-64 posi cases were weak dana's as pictured above. Many by this time have been replaced usually with a much better Eaton posi case.
The rebuild kits on the market are setup for the later,wider housings. Now this usually is 69-79 but I recently did a BB67 and it was a wider housing. It was correctly cast and stamped and came out of a car owned over 30+ years. I can't say why?
The difference is in the case shims, they are in the 070-090 ranges and I grind them to size to setup the pattern and final lash.
The bearing cap bolts and early caps are also different.
The R&P used in the 63-64 were also different with a coarse spline and thin crush sleeve. They are no longer avail so if you have one of these then you'll need a new yoke as well.
You can find all this info in the threads I have on Digitalcorvettes.com
Hope it helps. If you need help you can contact me. Brian Bair is a good guy and he can also help you out.

http://www.digitalcorvettes.com/forums/showthread.php?t=111107

[Michael C.]

Re: 64 Differential

I want to thank everyone for their help and making me feel welcome as a new member.