Hate to give you bad news dude, but sounds like if you have 1/4" side to side movement in the yoke you're pinion bearing is missing, or to put it another way, completely ground up. No wonder the safety lane grounded it. At this point I would think that the rear end housing is filled with metal and it would require a complete tear down and very, very thorough cleaning of the housing before reinstalling anything. Including the hubs, just incase the chips chewed up the seal and got into the wheel bearings. Chances are 99.9% that the rest of the bearings and gears are shot by now.
I would find that new pumpkin and spend a weekend cleaning out and flushing the housing. I bought one like this about 20 years ago and went through the same thing. The guy I bought it from told me that he just put in a new pumpkin. Only problem was he didn’t bother cleaning out the housing and the “new gear” was shot now also. After cleaning and putting in yet another new gear, I drove it for 50,000 miles before I sold it.
Who is “Randy’s” and where ya gonna find a 3.90 gear for a 3/4 ton? You mention that it is a 3600 yet you’re profile says 49 GMC, are the rear ends the same for both of them or is that 3.90 gear specific to the GMC? I sure would like to find a supplier for a 3.90 that would fit my 1950, 3600!
Denny Graham
Sandwich, IL
