If i get a posi unit out of a Blazer or S-10,can i just bolt on my ring gear and install it in my rearend without having to set up anything?I've never messed around with differentials before and don't know much about it.Anything i've read about changing gears makes it sound pretty daunting.I've looked for whole third-gen posi rearends to bolt in,but there seems to be a shortage around here.

 

Unfortunally its not quite that easy. You have to shim the differential to get the correct contact pattern on the gear teeth.

 

What he said. It's not hard depending on your mechanical abilities, but you'll need to know how to set it up.

 

yeah it's pretty much that easy. only a fool would shim anything to get the correct contact pattern. you need to keep the original total shim thickness when you swap carriers, however the arrangement of the shims can be changed from side to side to achieve the correct backlash, i'd shot for .008 + or- .002. check what backlash you have before you remove the original carrier and that would be a good number to replicate. when you have the BL set you can check the contact pattern just to make sure nothing is crazy wrong but all in all the contact pattern is fairly meaningless i nthe big picture and something that's pretty subjecting and hard to quantify.

 

The contact pattern has more to do with the pinion depth than the carriers shims. Having the right wear pattern set means that the gear teeth are meshing correctly. It's going to lead to longer gear life, less noise and less friction which means more power to the ground.....not much, but every bit counts. Have I slammed rears together without doing it just to get to the track? Yes, I think everyone has, but the right was would at least check to make sure it's close.

 

Your not going to change the pinion depth when replacing the carrier. Like said above, get the backlash right and the rest will be right too.

 

Don't think anyone said that it would.

 

Thanks for the help,That sounds pretty do-able to me.It helps to know what to look for before i jump in with both feet.