63 Pinion Flange / Seal (Joe Lucia?)

[Joe S.]

Joe (or anyone),

Remember this below as per Joe Lucia. Well I got the right flange. To install it I backed out the pinion nut and counted the turns. I Then removed the old flange and installed the new one. When installing it, I went the same num,ber of turns as when it came off and then a little more to snug it.

Now I have a very slight leak at the nose, which did not leak before. My guess is that the inside diameter of the seal is slightly different than the outside diameter of the flange. Probably extremely minor difference, but enough.

I need to get the correct seal but not sure what part number would go with the flange below.

Thanks,

Joe..

"The change to the 65-79 style pinion spline also requires a change in the pinion (companion) flange. The flange configuration that you described is new to me. I've not seen a 65-79 pinion flange of that configuration. Essentially, the 65-79 pinion flange is configured like the 63-64. However, the 63-64 flange is unique in cross section and you will not find a 65+ style flange exactly like it. However, as I say, the 65+ style flange is more-or-less configured like the 63-64 and does have the cupped shaped deflector and fits to the housing just like the 63-64. The GM flange is GM #3878972 and is still available from GM for a current list price of $96.44. All I can figure, based upon your description, is that the flange you have is some sort of aftermarket piece. "




Joe and Joanne's 63 FI Convertible

[Joe L.]

Re: 63 Pinion Flange / Seal (Joe Lucia?)

Joe------

I believe that the pinion seal is related to the differential carrier housing rather than the flange. In any event, below are the part numbers for the seals:

63-64-----GM #464140

65-79-----GM #3924031

[Duke W.]

Re: 63 Pinion Flange / Seal (Joe Lucia?)

Did you use a sealer on the splines?

Duke

[Joe S.]

Re: 63 Pinion Flange / Seal (Joe Lucia?)

"Did you use a sealer on the splines?

Duke "

I got the feeling my answer to that one is wrong. The answer is no! Think I missed that one in the manual somewhere.


Joe and Joanne's 63 FI Convertible

[Duke W.]

Re: 63 Pinion Flange / Seal (Joe Lucia?)

If you don't use a sealer on the splines they can seep, and you should be able to tell if the leak is from the splines or seal. Bill Bradley, who has a lot of recent experience overhauling Corvette axles, recommends GM Teflon Pipe Sealant, 12346004.

Whatever is used should be non-hardening so the companion flange can be removed in the future. I'm pretty sure the axle overhaul procedure mentions use of a sealer on the splines.

If the leak is from the splines you could try removing the nut, applying a sealer and then drive the nut back on.

Duke

[John H.]

Re: 63 Pinion Flange / Seal (Joe Lucia?)

Although a non-hardening sealer (like Permatex #2) was used in the spline cavity under the nut at Detroit Axle, Buffalo, and Warren for years, the Service Manual didn't pick it up and make it part of the companion flange replacement procedure until 1969. This area must be sealed or it WILL leak.