Based upon previous posts here, swapping a 12b for a 10b is porbably not worth the time. I have a friend that runs a drive line shop and he came up with a 12b that he just rebuilt with a Auburn posi in it with new 3.73 gears. Sine my Jimmy has open diffs I have been looking for a posi for it. He is asking $250 for it. The gears and posi have less than 500 mi on them and were professionally installed. Does this sound like a resonable deal ?