The Stovebolt Site Forums The Shop Area Engine Shop Rear End Seal

Hello all.
I have a '54 3/4 ton GMC and I just bought an oil laden 4.10 from the wrecking yard. I want to replace seal(s) and according to the manual, I need 1) an oil seal, 2) a felt gasket and 3) a gasket for the "seal retainer" = the 5 bolt apparatus that holds the pinion and yoke to the carrier housing. The parts seem readily available for 1/2 tonners but I haven't seen anything for 3/4 tons. Does anyone know where I can find these parts? Also, any advice on replacing these gaskets and seal?

The seal should be available at a parts store like Carquest or napa. I,m not shure about the retainer gasket although I have a GM part # at the shop. You can use RTV on it. I,m not familiar with a felt gasket. It,s probably not used anymore with modern seals. Tighten the pinion nut securly as it does not use a crush sleeve. Put in a cotter pin.

I'm assuming you have the standard 10 bolt differential, 10 bolts hold on the rear cover. If so it will be an HO52. If you need to, tell them it's for a 1970 model, this rear was used until 72. The seals and gaskets are the same. My local parts store has all the seals and gaskets on the shelf.

Also, you will need a redi-sleeve for the trunnion. It's a thin metal sleeve that goes over the polished shaft, which probably has grooves worn in it from the old seal. Last one I bought was $40, but without it your new seal will leak.

Check your breather cap, driver's side on top of the housing. Probably needs cleaned out, it screws in. If it is plugged, the oil vapor expands when heated and blows out the seals.

Thank you for the replies. It sounds like you've both found the parts at regular parts stores, but I can't imagine stores here in LA stocking these parts-everyone here drives japanese cars.

Fred T, my diff IS a 10 bolt, -does the redi-sleeve go on the trunion or the pinion shaft? Also, is this part readily available, and does it come in a standard diameter?

They may not have the parts in the store but they are associated with huge warehouses & get a shipment every night.

There should be a number on the old seal,take it to a Napa store and they can cross reference it to their brand. As for the gasket I usually make my own from gasket material. The felt packing is NLA but unless its torn up I just reuse the old one. Napa can also get you the speedy sleeve- just take the yoke with you so they can measure it and order the correct one....Mike

thanks for the info. I found a seal, made a gasket, and plan on ignoring the felt packing-there was non on the one that came out.