im having problems w the rear and am trying to figure out the best way to go about it that isnt going to cost me an arm or a leg lol im thinking of the locar junk yards here in san diego can i swap out a rear from a 4th gen? if i do something like that i would like to upgrade not downgrade but i heard that if i do that it will stick out more,thats a problem i'm running 275/40/17 rears and they almost rub now!---------well about my car 88 iroc 10 bolt---342gears disc breaks,i understand i have the aussi rearend? im thinking the best way is to go n get only the yoke n axeles mine are 28 spine,would that work? i dont want to rip out the whole thing if i can replace the yoke n axles only---any ways a: can i do that? n (b)what will fit in mine? thanks in advance for all the help you guys always seem to save my a** lol

 

The "aussi" rearend is the 9 bolt. If you have an 88 rear, it's 26 spline too, not 28.

 

ok so its a 10 bolt with 26 spline then? ok thanks what can i put in there then?

 

What do you want to get out of it?

 

Here are some issues you may wish to consider:

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC

 

well if i can swap in a stronger 4th gen w no headache thats what i want that will be the cheapest way and since mine's on the way out i need to start making plans dont get me wrong if i had 1500 to throw at it there is alot i can get out of it lol

 

but i still dont have a clue about what i posted"what will fit in my car" thats what i need to know

 

Humm, well, the link I posted pretty much tells you what'll fit. Good luck with your project.

JamesC

 

yep had a chance to look at the link great info! but then crawled under the car n found out its a 9 bolt then checked the center console and the (RPO) is a G80 about 5 years back i had the rear end replaced and noticed that it felt different,if 1 tire left the ground (uneven pavement) i would pretty much get stuck there while the other tire did nothing,ill rip off the cover in the morning, i think i might have gotten screwed,i have the feeling the guy kept my g80 n gave me something else,what #'s am i looking 4 on the ring n pinion if its a g80? and if it is a g80 what do i need to do as far as replacement? get a 12 bolt out of a 4th gen? how do i find out if the axles are 26 or 28 w/ out taking them out? i need help bad im taking a 1000 mile trip this week n need to get this wrapped up asap this isnt the type of problem i can fix on the side of the freeway

 

my problem was caused by the u joints breaking at 140ish lost driveshaft on the road ( aluminium) had to replace it w/ steel one from a 91rs now (on jackstands) i get severe vibration from the wheeles on the freeway @ 65 it does vibrate but not as bad as the jackstands, in reverse it feels really weird so thats how the replacing the rear came about plus when i had it redone the guy told me i needed to replace the axles because they are notched.

 

No 12-bolts in a fourthgen (all are 10). Your 9-bolt will have 28-spline axles. More homework:

https://www.thirdgen.org/forums/faq-...now-about.html

JamesC

 

Your 9 bolt is the strongest junkyard diff you're going to find that's going to fit. The chances of finding one of the rare Dana 44 diffs is very slim. The downside to the 9 bolt is that parts are just about non existent. As for the 10 bolt, the 90-92 third gen diff is the same strength as a fourth gen diff. The fourth gen diff is just wider.

If your 9 bolt is on the way out, your best and easiest swap is to find a 90-92 third gen diff.

 

Wrong. The parts are out there, just not as easy to find in any store you go, as a 10-bolt.

I'll take the strength of my 9-bolt, over the availability of easy to find 10-bolt parts. 10-bolt parts are easy to find, because 10-bolt brake so easily.

 

While they can break easily, I think parts are easier to find because there were 9000 times more of them made.

 

Yep. The $ is in fixing stuff, not making it. Why do you think GM stopped using the 9-bolt? They sold way less replacement parts!

 

The 9 bolt isn't a huge amount stronger than the 10 bolt. It's designed differently but it only has a 7.75" ring gear instead of a 7.5/7.625" ring gear. If you're producing enough power to break them, you should be upgrading to an aftermarket diff.