1969 differential front seal

[Bill Stephens]

I'm replacing the front seal in the differential of my 1969. The manual calls for a spacer between the seal and the differential (tool # J-22804-1) when installing the new seal, but doesn't say how thick it is. The current seal has about 40/1000 inches, but it's not completely even. How much distance should there be between the seal and the differential? Thanks.

[John H.]

Re: 1969 differential front seal

Bill -

The '67 Chassis Service Manual calls for a 1/8" gap between the seal flange and the nose of the diff; the parts are all the same as '69 and the tool isn't called out in the '67 manual, so they must have released the tool and added it to the seal installation procedure in the '69 manual to ensure that the seal wasn't driven all the way into the bore.

[Joe L.]

Re: 1969 differential front seal

Bill-----

The seal installation tools are long-since discontinued by Kent-Moore. In addition, later editions of the Corvette service manuals dropped reference to the use of the tools, even though the differential carrier case was the same from 1967 through 1979.

I really don't think that the use of the tools is necessary for 1967+ Corvettes even if the 1967 to ???? editions of the manual call for it. I think that this reference may be an "anachronism" which "crept into" these manuals. Earlier versions of the carrier case MAY have required the use of the tools and, thus, that was appropriately specified in those earlier editions of the service manual.

For the 1967+ case, I believe that the seal orifice is of slightly larger OD than the remainder of the pinion shaft "tubular section" of the case. Consequently, for these cases there is an effective "seat" for the inner end of the seal. When the seal is tapped into the case, the rear end of the seal shell will bottom on this "seat" before the flange on the front of the seal shell "seats" on the end of the "snout". So, the space between the flange and the snout will be taken care of "automatically".

I THINK that earlier versions of the case (i.e. 63-66) did not have the seating provisions for the rear of the seal shell. So, for these cases, the use of the tool is necessary to prevent over-insertion of the seal shell in the carrier case.