my 91 has a crappy 2.73 2-series open rear end, I have the 86's 3.42 rear end and it won't be used in that car anyways, so I'm thinking of pulling it, will this work:

pull the axles and diff. out of the 86 and put the 28 spline axles from the 91 in there and get the slp posi since it is for the 28 spline axles

 

the SLP posi is the differential, use this along with the set of 3.42s out of the 86 (if they are still in good condition) and your set to, youll also need an installation kit.

 

thanks for the help, but I got all that, I just what to make sure that the slp posi made for the later year housings will fit in the 86 housing, I don't want to install gears in the 91, its easier just to swap axles

 

im not understanding what youre saying....

what i am hearing is....you are going to remove the differential from the 86, then put in a SLP posi unit and your 28 spline axles....but by removing the differential from the 86 you are also removing the gears, so y not just install the 3.42s and SLP posi into the 91 rear end. Seems like this would be a whole lot easier.

And your not just swapping axles into the 86 like you are saying, you are remove the axles, remove the differential and gears, installing the new SLP posi unit and reinstalling the gears, then installing new axles.

 

Let me see if I have this right....You're wanting to put a posi and axles out of an '86 into a '91 housing? I did pretty much the opposite in mine. I have an '82 and I put in '91 axles and a '96 posi so I'm betting that it will work for you.

There is one thing to consider. Does your car have anti-lock brakes? I don't know if that was ever an option on these cars (maybe only 4th gen) but I do know that the inductor ring for the anti-lock brakes is on the carrier. If you do have anti-locks then I don't think it will work.


-Tony

 

you had most of it right, but I AM keeping the gears in the 86 housing, I just want a cheap posi, slp only makes them for 28 spline axles, which I have in the rs, so if I take the 28 out, put them in the 86 then add a slp posi, thats were I want to be

sorry for the confusion, I wish I would just talk instead of type, that would clear everything up

 

you make it seem like you can just add a posi to your rear end without doing anything else, its not that easy, you might as well just swap the 86 gears and SLP posi into your 91 rear end, that would be alot times easier. I dont think you are getting the entire picture of how the differential and gears are set up.

 

If they're both drum brakes (which it sounds like), then the 91 housing is no better than the 86 housing.

There's no reason you can't swap a carrier into a rear end. It's a whole lot easier than swapping gears. If you don't have the tools and experience, you're better off leaving the gears (specifically the pinion gear) alone.

Yes, you can take the SLP posi, and stick it in the 86 rear end, using the 86 3.42 gears. You dodge the necessity of fooling around with the pinion gear that way, you won't have to touch it; your factory carrier shims will probably go right back in and produce acceptable backlash. Check the amount of backlash the rear has before you take it apart, with a feeler gauge (should be in the .006"-.012" neighborhood); and make sure it has about the same amount when you put it back together. You might want to buy a shim pack (I paid $12 for one the other day) just to be prepared. Definitely replace the carrier bearing outer races. Then, yes, you can put the 91 axles in there. Again, definitely put new axle bearings and seals in the 86 housing when you put the other axles in it. Then swap the 86 housing into the 91 car. Done.

 

rb83l69 that is exactly why I wanted to do, and thank you for telling me it'll work

vjo-I'd rather swap axles and a posi over a diff any day, you are either crazy or a good diff man

 

but isnt the posi the differential?

 

OOPS sorry about that I meant to say posi over a set of gears, and you must be a good gear man, I was running late for work, I wasn't worried about double checking

 

i think i was just alittle confused, i was thinking that by removing the differential and the gears would in essence be the same as doing a gear and diff. swap, but i guess it is just easier to remove the ring gear and swap the diff.. We're all here to learn, i guess i just learned something.

 

vic always says "you have to learn something new everyday, otherwise you'll turn out to be one of those know it alls that I hate"