$500 shipped to lower 48

 

PM Sent.

 

11971four4two got a question since I will be in the market for one of these what is the difference between 671,672,673 posi units for type O axle is it splines? or gear ratio it can carry. I got a set of 3:08 gears for O axle that I need a posi carrier for Thanks I know I got to pull a axel to see how many splines I got.

 

Jopa, here is a good write-up on the differences. You are correct in surmising the gear ratios they can carry are the determining factor. Only one has a different number of splines - that is the 672 carrier.

 

Jopa, if you can find/determine the two-letter axle code on the passenger side axle tube, you won't have to open the rear end. The code stamp may be hard to find under road grit and grime, under coating, etc.

 

Thanks that is a big help car came with 3:23 posi on build sheet for whatever reason they where changed to 2:56 posi so they had to change carrier to accept 2:56 ratio so im guessing it still has 28 spline axles Thanks

 

Yes, 28 spline shafts were the only ones used on the 3.23 and 2.56 rears.

My guess would be someone swapped the entire rear and not just the gears and carrier. An R2 or R3 code stamped on the axle tube would verify that.

 

Thanks fun71 i'm 3rd owner the person who I purchased car from his uncle was original owner, 2nd owner changed ratio I did not ask him why either it let loose or for gas milage/drivability its a TH400 but he said that is the original rear end I will have to check for myself,car was in same family all its life, it is well documented, I even have receipt when it was changed.

 

This is a pic the day I bought it.

 

WHOA Daddy
That is a fine ride