You can use these GMC Group numbers Bill Hanlon to verify this stuff , this is what I came up with as I was checking the data for the H052, early HO72 GM Differentail data. Then cross checked for the GMC. Please review and correct me if needed. I am not an expert on GMC or GM Rer Diffs. The HO series were produce by Eaton and have many common part numbers, exceptions do apply to second series HO72 use after 1960.
Good Morning - edited , GMC H-072 , H-050, 1 st series H150 ?? Here's what I've uncovered, same parts as GM HO52, early H072.
The seal is a National 411330N, or Precision 41133 ON. Readily available at your local parts store. (GMC Group 2.1610 a or E , Seal, # 3653618)
The felt packing is National 5M89 - and its not readily available. You may be able to use your old packing by placing a couple layers of silicone near the front of the cleaned up oil free retainer to reduce the OD of the retainer in that areea and that may allow the felt to squish out further. Some say you don't need it with the newer seal. It was meant to be a wiper to help keep out dirt and grime I'm told. ( GMC Group 2.1750A, Felt #3653617)
The paper gasket is Gm # 3682147 - (Alsao GMC Group 2.1310 A or E , Felt, #365317) . They pop up on Ebay once in awhile. You may find one using Partsvoice.com. You can proably use silicone sealer in its place since this is not a crush washer application, joint thickness is not a concern and again helps place the seal to shaft interface in a new location. Reducing the need for a redi sleeve. Just be sure to polish up the pinion shaft using scotch bright and PB blaster or other suitable rust/varnish buster.
Before you remove the nut and cotter pin, Mark the nut and pinion shaft with a center punch point. This helps on reinstall and torque of the pinion nut for alignment of the cotter pin holes. This diff does not use a crush washer. Just torque, align dots, insert cotter pin... torque to 180-200 ft lbs , watch the marks as you approch those numbers
To help remove the nut ( a big impact wrench helps with a 1 5/8 " , 12 point socket, 3/4 drive . OD of socket turned down to 2.140" to clear inside of yoke. Placing a large pipe wrench over the yoke and letting it rest of the floor really helps with removal and install. Trust me, I know.
Hope this helps. I've attached a "blow-up" illustration and pages from GMC Parts Pages 1963 master parts listing, Apologize for the quality, but it may be useful.
PM me if you need more input.
Last edited by Dusty53; 10/19/20235:09 PM. Reason: detail, reference to GMC part numbers
Ron - - Dusty53 1954 Chevy 3604 In the Gallery Forum "You can't dance with the Devil and then wonder why you're still in Hell." "They will forget what you've said, and they will forget what you have done but they will never forget the way you made them feel."
