Rear Axle codes

[HOTSIX]

Im looking at buying an 8.5" 10 bolt rear end a guy claims came off an 87 GN. I have no reason to doubt him.

Its got the stamping on the pass side axle housing about 3" away from the diff - "3TR G065".

I can't find this code anywhere on the net so far...anyone able to decipher it ?

The numbers on the ring gear in the diff are "2 GM 3988518 11 41 2 86".

I know the 11 and 41 are the tooth count for the pinion and ring gears which works out to a 3.73 rear gear. I also know that the 3988518 is a GM part number...but whats the rest ?

Its in great shape inside and out. No wear on the clutches and gears (look new / replaced recently). Also - what do you guys think its worth ?

 

[Brian Mc]

Sounds like an olds rearend from a 86 442. is it 8.5 for sure? either way it's rare and good to pick up while you can.
worth 6-800

 

[Black Sabbath]

All 87 GNs came with 3.42s from the factory so that rear end is not out of a GN if you are sure about the ratio of that rear.
Not to say that it will be a bad deal but it did not come from a GN.

Brian

 

[HOTSIX]

Brian - How you know it's from an Olds ?

I don't know much about rear ends (except the other kind... ) so how would I check that its a 8.5" ? What's to measure...the ring gear ?

The guy said it was an 8.8" but I figured he was mistaken cause I know all GN rears came 8.5".

He wants $325 (was at $400) for the rear complete and will throw in 2 South Side Machine bars (boxed control arms) with the deal. They look relatively new (bushings and zerk fittings included).

Jump on it ?

 

[turbofish38]

The codes in the Olds catalog list a TR code as being 3.73 ratio with limited slip. I think the number 3 should be the number 8 and the letter G means it was built in 86 on the 65th day of the year. Looks like your axle came from a 86 Olds Cutlass 442. Thanks Eric Fisher

 

[HOTSIX]

Hey, thanks for the decipher.

I bought it and hope to have it in the car in early spring, along with the SSM boxed control arms.