[jeffh]

I have an 89 2WD Reg Cab Long Bed S10 Chassis that i was told once housed a 6cyl but was changed over to a SBC. I never had the whole vehicle so don't have any codes etc. I also have a 2006 Silverado 2WD 6cyl parts truck. I was told that this truck has a posi rear and that i could simply swap the guts over to the s10 to make it a posi rear. Is this correct? Do i need to do anything with the axles?

 

[Tranzman]

most S10's had a 7.5"/7.6" axle and Silverado's had a 8.5"/8.6" axle. Unfortunately the two differentials are not interchangeable. I would hunt down a G/U differential from a salvage yard that has G80 on the service parts sticker in the glove box. You may even fine the same gear ratio diff.
If you look at the sticky at the top of this sections on rear end info, it will tell you how to tell the difference.

 

[manbearpig]

I'm not sure what rear the Silverado has but I'm 100% positive it's not a 7.5 like you have. Unless you've got some modified rear end that is the same as the Silverado's, not going to work.

If you want a posi out of another vehicle, you want the auburn or torsen out of an F-body.