The Stovebolt Site Forums The Shop Area Driveline Pinion Seal, 1954 Chevy 3600 , leaking gear oil

I need to repair the leak from the input shaft on the rear differential. The parts books don't list a pinion seal for a 1954, but they do for the later years, example - 1972 C20 with Eaton HO52. Shows an SKF 25970 seal and National 5M89 Felt seal. The Shop Manual describes and oil seal and packing, but it isn't too clear to me. What do I need to know to get this right the first time? Help, please.

rockauto shows these for 1954, but you will have to determine if one/both fit a 3600?

http://www.rockauto.com/catalog/raframecatalog.php?carcode=1326473&parttype=2380

NATIONAL Part # 411330N
Rear Outer; GMC H072 (Only 6 Remaining)
$11.31

Hy Dusty53 your SKF seal number is correct also the same as National p/n 411330N. As far as the re & re, remove the driveshaft hold the pinion yoke with a large pipe wrench braced against the ground or frame or something solid, remove the pinion nut and remove the yoke. You can probably pry the old seal out and replace it with the new one. Inspect the yoke for a groove in the seal surface, if you find a groove you should install a Speedi-Sleeve to give your seal the best chance of sealing and surviving for any length of time. If you do need a sleeve take your yoke into your Friendly Local Auto Parts Store (F.L.A.P.S.) so that they can measure it and order/supply the correct sleeve. When all your pieces are ready for assembly put everything back together and torque the pinion nut to the correct torque, use the pipe wrench again to hold the yoke, Do not count on the tire/axle to hold the yoke, ring and or pinion teeth have been known to break when the yoke is not held by some kind of device, this is especially true if an impact wrench is used, hope that helps.

From that same Rockauto.com page:

NATIONAL Part # 99259
Redi-Sleeve
Rear Outer; GMC H072 (Only 1 Remaining)
$25.99

Thank you Tim and thank you 3B , that covers the seal perfectly, what about the "packing" is it replaced by the felt ? Will I need the Felt Seal that is also shown in the parts list for this online ?

Hy Dusty53, I believe the "packing" was the felt, and I believe the felt was eventually discontinued as well. However you already posted the part number so you could purchase one and install it if you like. I am not sure about the number that tclederman posted for the sleeve for the pinion yoke, in the part description it says "Rear Outer; GMC HO72", not pinion yoke. I'll see if I can confirm the sleeve part number, hope that helps. Okay I have confirmed the sleeve part number is correct for the pinion yoke SKF 99259 SKF p/n for the felt is 528 (it was discontinued in 1960)

3B , you've been a great help. The "felt" part number was described as 'Felt, pinion", the description lists a shaft size of 2.500", and outer diameter of 3.438" and a width of .313". I noticed the OD is smaller than the "seal" OD which is 3.486" but assumed that it gets compressed and probably acts as a means to keep out dirt, etc.... does this sound right to you? Last question, I hope.

You will need to remove the 5 bolts & take the flange off to remove the seal. It comes out the back of the flange. There is a special gasket that goes behind it. You can use a heavy bead of RTV. There is no crush sleeves on this rear end. You can tighten the pinion nut securely & tighten it line up the cotter pin hole.

Wrenchbender, thank you for the directions, its appreciated. I think I just might pull this one off without breaking it! Thanks to all who've responded.

this is old news but I have a new one on a 50 chevy 3600 pinion seal

u joint yoke fits on a splined shaft ,,, where does the seal go ?

The seal runs on the outer surface of the u-joint yoke where it slides onto the splined shaft.

I have a '54 3600 that needs to have this done. I am not very mechanical however my local mechanic is hesitant to perform this as he feels he would need to approach the pinion seal from inside and remove the differential gears. For those of you that have replaced this seal does the advice from "3B" up above in the thread hold true? Can it be done externally?

Any step-by-step advice would be great. I have the seal and will probably need a sleeve. any help would be appreciated.

Thank you

Your mechanic is wrong. the pinion doesn't have to come out. Just unbolt the yoke and the retainer. Actually a pretty straight-forward job.
Here's a blowup of the differential

Thank you

Hey MTCTH , based on my own experience I recommend you consider purchasing a "Chevrolet Truck Shop Manual 1954 Models" . There are reproductions available from most of the parts suppliers and sometimes originals are found on Ebay. It'll pay for itself very quickly.

In the mean time, while you possibly seek a hard print copy of a 1954 Chevy Truck Shop Manual as Dusty53 suggests, you can access an electronic copy HERE courtesy of the Chevy Old Car Manual Project!