chev 12 bolt
 

a have a 12 bolt rearend was wondering what it came out of #3894860nf tube #bm 0213g2 A279 con1 can anyone help?:confused:

Re: chev 12 bolt
 

68 Chevy II with 3:31:1

Re: chev 12 bolt
 

would you know if it was originally a posi unit. and i thought that the last number on the housing was the year?:o

Re: chev 12 bolt
 

BM is a 3:31 OPEN NOT a posi

Re: chev 12 bolt
 

could someone have changed the case because if i turn one side or the other both sides turn, even when i turn the pinion. inside it looks like on each side there is a plate w/springs. thanks for your help.Paul:confused:

Re: chev 12 bolt
 

The ORIGINAL rear end that came from GM was a 3:31 open gear---that is not to say that somewhere down the road it has not been changed to either a POSI or an entirely different ratio--- but as originally manufactured it was a 3:31 open ---sounds like ya got a posi in there whats the numbers on the gears???

Re: chev 12 bolt
 

the ring gear has #3093 419 usa y ? 1x on the case # ed3 30174 another # e 2 10:confused: does those numbers help you any ?