alright guys i'm buying a limited slip differential this weekend and i still haven't figured out how many spline axle my car has. i'm going to wing it and get a 28 spline axle limited slip differential. if for some reason my trans am is 26 can i just buy 2 new axles that are 28? if i do that would i have to order them for a 90 trans am or camaro? thanks

I think you are wasting your money buying something that may or not fit. For example: What rear do you have a 9 or 10 bolt or a 2 or 3 series carrier??
Because the axle shafts may not be your only problem.

1990 and up will have 28 spline axles.

However: He has a 1989, so no help. He needs to answer some questions first before he spends money on a may be useless part.

i'm pretty sure it's a 10 bolt i'll double check that tomorrow and it's a 2 series carrier.. if i can't buy a posi can i just go to the junkyard and buy a whole rear from a 90-91 and be able to use my gears and posi?


yes it is an 89.

quit being lazy! get the *** end of the car off the ground and get under there! pull the cover, pull the spider gears, pull the axles out, count the frickin' splines! your gonna regret it when you get into your project to only have to put it back together with the stock parts and wait longer and spend more money to get the right parts. if i were you, i'd make sure you either have the 28 spline axles now, or upgrade all at the same time, instead of pulling the car apart a bigillion times. JMHO.

ok so i will take my rear apart first and count the splines. if it's 26 or 28 why wouldn't i be able to make it a posi?

there is no reason you wouldn't be able to make it a posi, manufacturers make posi's for both. but the 28 splines are a bit stronger. i'm in the middle of the same upgrade myself, except, i am going with some aftermarket Moser axles.

I just went through all this ....now I have an extra posi sitting around. But it was my fault because I went all cross eyed trying to count the dam splines LOL . My 1989 had 26 spline axles but it was a 3.08 posi

If you can find a 90-92 in the junkyard then you might find some factory 28 spline axles to use. The 28 spline axles, either factory or aftermarket, will fit into all third gen 10 bolt housings as long as you use a 28 spline carrier.

If you have a 1989, then there's only a very slim possibility that it has 28 spline. Only cars near the end of the 89 production run got them and there weren't very many.

Aftermarket axles will list 28 spline axles for 90-92 only because they would be considered replacement parts. I bought mine from http://www.tomsdifferentials.com/ for $125 each and put them into a 1986 housing with a 28 spline carrier.

Again I will throw the BW 9-bolt into the Mix and really screw up his plans if it is. 89TA could have one,,,,

so what if i have the 9 bolt? i can't get a posi or my gears? if i have a 9 bolt i'm saying can i get a whole rear from a 90 or so? with a 10 bolt?

With the above statement. You should do a little more research to get a clearer idea what is involved and the limits of what can & can not be done in your situation.

How do you know it's a series two carrier....what gears are you trying to use vs. what do you have already

2.73-3.08 series two
3.23-4.11 series three
over that series four

There are exceptions to the rule for aftermerket gears ...but I won't confuse you more with all that.

i have a 10 bolt rear, 2.73 gears.

i've done research on it already i wasjust asking if i ordered a 28 spline axle differential and i had 26 spline if i could get 28 spline axles to work.. because the differential would be a 28 spline