12 bolt rear end

[Ryder73]

Hi everyone. I'm new here and got a question about rear ends.
I have a 85 gmc sierra classic 2 wheel drive. It has a 10 bolt rear end. I purchased a 12 bolt rear end to replace it. I have a bunch of casting numbers from the 12 bolt and just trying to figure it out what it is from. Why I'm asking is because I'm buying a locker of it and want to purchase the correct one. Any help will be great.

Gm 81

3896839
N

KDD 078W91

Inside on the gears it says 10:34 gm

These are all I found so far. If there is more please let me know

Thanks
Adam

 

[bucket]

Where did you get it from? Does it have leaf spring perches on it or coil spring perches? Is it supposed to be from a truck or a car?

 

[Ryder73]

Got it from a guy who has lots of truck and parts. He said he took it out of a 1978 1/2 ton chevy.
It has leaf spring perches on it

Also found other marking on axel st(either c or g) can't make out which one.

Any info will be great

 

[Ryder73]

Anyone out there can help me????

 

[bluex]

Can you post a picture of it? Really any locker for a truck 12 bolt axle should work though.

 

[Pender1]

KDD - C10 1979 3.40 non-locking