I don't have pictures of my rearend but the numbers on the ring gear is 1358138-11.39 GMC and the pinion has 1358139 B-11-39 if that helps
Well that is NOT a 8.5 GM never made 3.55 gear ratio for the 8.5 rear end. So 8.2 Buick or Olds from 1964-1967 or Pontiac from 1964-1972 10 bolt 8.2 is what you have. You sure there is not any other numbers on the ring and pinion ? How about the housing any casting numbers? Geez pictures would be Soooo much better.
I didn't see a thing on the housing. I'll try to get pictures in the morning after work and upload them. I need to get parts ordered so I really need to figure out what I need. Thanks for helping. This is very confusing. Lol
I've got two Eaton clutch style and 2 Auburn cone style posi's in my cars - My observation (from about 1000 passes with all 4) is the Auburn cars are much more pleasant to drive, and have more consistent posi action in the burnout box. However, they are lighter duty and will wear out fairly quickly they way I'm using them (have one going out in about 400-500 passes). The Eatons are heavier duty and work well, but are finicky in the burnout box and chatter when hot around corners, even set up loosely. Ultimately, for what I do I'd choose the Eaton style, but for a light duty cruiser I'd choose the Auburn....
Ok. BOP 8.2" cone unit. Now,what pieces are broke? It looks like the one side of your pin bore is getting sloppy.
spider gear will not have sufficient support where the cross shaft case and spider gear thrust washer meet. casting got mangled pretty good if you look close. I am sure the spider is gone and shaft has tons of debris or gouged pretty bad. Those early units are weak anyway... RIP Show some pictures of the cones for condition of the unit there. That is a BUICK 10 bolt 8.2 it is not Pontiac, Bearing cap is a DEAD give away. Any 64-67 Buick, Olds or Pontiac gear will fit that 65 rear. The pinion seal is 8620 Buick seal
Look at the unit only 5 casting webs hold the bearing hub secure... Like spokes on a crager wheel BUT MUCH thinner...lol. Red circles The whole blue area is pretty weak. the other none ring gear side is the same way...They left it open to keep the cone waste debris moving out of the units inner area WHICH i am sure works BUT really weakens this early style unit. 4 pinion spider gear unit does not have these waste releifs which just increases strength and with 4 pinion spider gears and small 1" window the unit is just superior to the 2 pinion small shaft unit. The failure most likely came from the cones bottoming out in the case and the one wheel would spin violently on a burn out making the spider gears spin crazy fast on the cross shaft creating a magnetic field then all the silt metallic material was drawn to the cross shaft and spider gear spinning area, fusing it together almost like welding. then seizing the parts and the motor will over power it making the spider gear fail...explode etc. Hope that make sense... Happens a lot on open non posi diffs when people do too many one wheel long burns over and over and never change the oil. Jim J D
