63 pinion yoke

[mario diteodoro]

Im looking for a small dia.(I think it is a 1310)pinion yoke for a 63. It has a large dia. (1350 i think) in it that is hitting the tunnel. Thanks Mario.

[Joe L.]

Re: 63 pinion yoke

mario----

The 1963 pinion yoke (companion flange) is unique to 1963. Functionally, you can use either the 1963 or 1964 yoke. You cannot use a later yoke since the spline count is different. However, you may, in fact, have a later differential unit (or, pinion gear) installed in the car. I don't know of a larger series flange that will work with the pre-65 flange. So, the first thing that you need to do is to determine what the pinion shaft spline count is on the differential unit that you have.

[mario diteodoro]

Re: 63 pinion yoke

Hi Joe. It has 30 spline and looks to be 1.625 in dia.

[Joe L.]

Re: 63 pinion yoke

Mario-----

You have a later differential or pinion shaft. So, you need a GM #3878972 flange. It's the same size as the ORIGINAL flange used for 1963, but will have 30 splines as used for all 65+ differentials.

Unfortunately, it's GM-discontinued. However, replacements may be available. It was not a Corvette-unique piece. It was used for many 1965-68 Chevrolets with 12 bolt cover differentials.

[mario diteodoro]

Re: 63 pinion yoke

Thanks Joe. Do you know if the large yoke can be made to work (shimming the nose of the rear down for clearence)Or is the 1310 the only way to go. Thanks Mario.

[Joe L.]

Re: 63 pinion yoke

Mario----

Changing the yoke is the only way to go; there's no way to shim or modify it. However, changing the yoke (and, consequently, u-joints will also require changing the driveshaft or the yoke welded to it. That is, unless you are currently using a conversion u-joint (different size finger diameter for each opposing sets of fingers).

I don't really understand why you have the larger yoke in there now. All I can figure is that someone changed the differential unit and the one they used had the larger yoke. So, they used a conversion u-joint or changed/modified the driveshaft. You need to "undo" now whatever they did to get it right.

Changing the pinion flange is not a really easy thing to do and that may be why they left the larger flange on the unit and "otherwise dealt with making it work".

[mario diteodoro]

Re: 63 pinion yoke

Thanks Joe. I found a place in Buffalo NY. called Denneys Rears? 1-716-875-6640 who had 3 on the shelf for 30 spline small u-joint- He now has 2 @ $59.95 each. The drive shaft is for the small joint. Thanks for all your help. Mario