Ok, i had an 86 IROC but was hit and rolled and my rear drivers side tire snapped off, busting the axle. Now if i'm not mistaken the IROCs and posi differentials in them right? I know that i used to be able to spin both tires anyway.

Well i just picked up an 84 Z28 with a T5 transmission but its just one wheel peal, no fun

So my question is how hard of an instal would it be to put the posi differential in the 84 rear end? I already have the 86 IROC rear end tore apart and see that the ring gear bolts up to the differential.

So basically what i was wondering is if the two different differentials have the same bolt pattern and how much re-shiming i'd have to do to the rear-end if any by switching from the limited slip to the posi.

Thanks for any help,
Seth

 

both 26 spline 10 bolts? if so the carreirs would be a direct swap. you'd have to make sure you had the same series carrier to match your gear set. it wouldn't require any more shimming than any other gear swap.

 

Thanks alot for the help.

Just to be clear, the number of bolts holding the cover to the back of the carrier is what determines the series of carrier right? If so then yeah they are both ten bolts. Havnt pulled the axles out yet of the 84 rear-end to see what spline they are yet.

Now about the shiming, do i have to get a whole bunch of different thicknes shims and keep trying till the gears mesh up, or will it be the same with the ones that were in there?

Thanks again

 

yes it's the number of bolts holding the rear cover on, if it's pre 89 you have 26 spline, 89 can go either way and 90 and later are 28 spline.

 

I just talked to a couple of my dads mechanics and they said the same thing, that if the carrier are the same series and the axle splines were the same then swaping the posi in shouldnt be to complicated.

Once again, thanks for all the help. Dont know what i'd do without this board.

 

Not too complicated, but you need to get is exactly correct. Posi it GM's name for limited slip (they are the same thing). One other thought...how is the Iroc's differential case and axle tubes? If the only problem with the Iroc rear is the axle, just toss the 84 axles in the Iroc rear and install the whole thing.