Hello


My car is a 1989 (MAF) 305 TPI Auto Camaro with the stock 2.73 Posi Rear end. Now i want a little bit more acceleration and therfore a change to 3.42 posi.
What parts do i need for this swap ? Is it possible to keep the stock posi carrier ?


Thanks

 

You need the thick 3.42 gears that fit a 2 series differential, and a good installation kit. There are only 3 kits that I can recommend. Tom's Differentials, Yukon and USA Standard kits are good. Almost all of the others are junk. I would also recommend a US Strange or US Gear gear set. Tom's Differentials and Quick Performance are good places to get these parts.

 

I can tell you go going from the lazy 2.73 gears to 3.42s it will definitely feel like a different car. I went from 2.73-3.73 and wow what a difference and only about 1.5 mpg difference on average is what ive noticed. Good luck!

 

If your going in there anyway & going thru the hassle of setting up the gears & everything why not upgrade your posi at the same time? You can find a used TORSEN with 3.42 gears on Ebay out of a 99-02 SS/Trans Am. Probably cheaper than what you're looking to spend on just gears and the posi units are way better.

 

The '89 would likely have 26 spline axles, so an upgrade to 28 spline axles would be required to do the Torsen. I do agree that the original Auburn should be replaced.

 

Here's what I did and it changed the way the car performed 100%.
= https://www.thirdgen.org/forums/tran...de-photos.html
Its a long thread but there's a lot of information in it concerning the subject.

 

I am from Europe and used parts are a big problem. You think a modification of the original posi is not worth it ? My car has actually ~ 260HP

 

You can't modify the Auburn differential. It's a cone type limited slip differential and when it wears out it's scrap metal. You can not rebuild it. The Auburn wears out quicker than other brands and fills the rear end with powdered metal sludge. This is why it is recommended to replace it with something better.

 

****, that is not what i want to hear. My car has only 60000Miles on it.
If i change to a torsen diff, which parts do i need ?
Which parts of the Auburn diff can be reused ? (Axles, ...)

 

depending on how the car was used and with only 60000 miles,the auburn cone posi might still be in good condition-will just have to check it.

 

If the car was driven normal then the Auburn is probably still god. If you plan on doing burnouts then it might not live long. Water burnouts and burnouts while holding the brakes will kill it very quickly. Also running the rear tires with unequal air pressure or tires with uneven tread wear will wear it out.


You would need to swap axles to do the Torsen swap. Your car probably has 26 spline axles and all of the Torsen units are for 28 spline axles.


You need to read the FAQ about 10 bolts sticky and look at the different series differentials for different gear ratios, axle splines and other information about these rear ends.

 

If my Auburn Diff is in good shape, is it possible to change only the gears (with a ring set) to 3.42 ?

 

Yes, you can use the thick 3.42 gears and use your 2 series Auburn. I would highly recommend getting a good installation kit. You will need shims no matter what, and they come in the kit. All of the other small parts that you will need are also in the kit. New bearings are a very good idea, even in a 60,000 mile rear end. The USA Standard kit is the cheapest one that I can recommend that is not junk.

 

How can i check my auburn diff for any damages ?


Thanks

 

Are that the right parts for my mods ?


http://www.usastandardgear.com/produ...px?ProdID=6597
http://www.usastandardgear.com/produ...px?ProdID=1067

 

Yes, but don't be surprised if the gear makes noise. The USA Standard gear is an economy gear that is known for gear noise no matter how well it is set up. I like US Strange and US Gear better. You can get them from Quick Performance, along with the USA Standard installation kit.

 

My rear was pulled out of an 84 Z28 with only 40k miles and I may only have 500 mi on it and myself have not been hard on it and my differential is showing signs of being wore out. So I could see one having some wear at 60k mi.

 

What would you think about Richmond or Yukon ?

 

What do you think about Richmond or Yukon ?

 

I installed Yukon gears for many years when I had my rear end shop and almost all of them were good. I got a few that made noise, but I also got a few of just about every other brand that made noise. I like the US Strange gears right now. They seem to be some of the best. I can't comment on Richmond at this time. I haven't installed any of their gears in years.