If your buying a new posi unit for a 91 firebird, which would you get. And pros and cons of either brands. Eaton, Auburn etc... I am looking at a true limited slip, not ratcheting lockers etc.... thanks

 

My opinion is that the Eaton is the best all around differential for the GM cars. It will last much longer than the Auburn and it can be rebuilt if it ever does wear out. It can also be tuned to fit your needs. If you are going road racing or auto cross then the Truetrac or Torsen might suit you better.

 

Everyone talks about how the Auburns are not DIY-rebuildable, and that's true, but they don't wear out very fast, either. I've had them still fully functional past the 130,000-mile mark. They're the best for snowy roads, probably part of why GM installed so many of them in f-cars. The Auburn Pro really isn't worth the extra $. If you're going drag racing with a manual trans, forget the Zexel Torsen. They fail first.

 

Everyone talks about how the Auburns are not DIY-rebuildable, and that's true, but they don't wear out very fast, either. I've had BOTH of mine still FULLY functional past the 130,000-mile mark. They're the best for snowy roads, probably part of why GM installed so many of them in f-cars. The Auburn Pro really isn't worth the extra $. If you're going drag racing with a manual trans, forget the Zexel Torsen. They fail first.

 

it is for a street strip car. stock 305, just something for my girlfriend to learn in. I dont really plan to have here shreddign the tires in the water box. Just looking for the best bang for the buck. Let me get this clear though. My car was originally a 2.73 rear. I just installed a 3.73, but I should still get the posi for the 2.73 and lower carrier correct? I assume It has something to do with the housing. Just want to make sure I dont order wrong. Thanks guys

 

It's the differential series. The 2.73 uses a 2 series differential, so I assume that you used the thick 3.73 gears to fit the 2 series. If that's the case then you need to get a 2 series to replace it. This causes a problem for you because all of the after market differentials are 3 series. There were never any 2 series Eatons, so that leaves you with a used 2 series Auburn, Governor Lock or Torsen. I really don't recommend a used Auburn because it might be worn out before you buy it. The Governor Lock isn't very strong and will probably fail under hard use. You might need to get another set of gears so you can use a 3 series differential.

 

oh this is getting better buy the minute. Jeez dat sux!!

 

http://www.jegs.com/i/Auburn-Gear/109/542041/10002/-1
wouldnt this work.

 

I was gonna say you don't have to go used to get a 2-series Auburn, but you already found it. But when she does sneak off to the dragstrip, she needs to be sure both tires are in the water box, you don't want to be at full throttle with only one tire biting, like when pulling away from a curb in winter.

 

ok so I think that unit will be my only choice. as far as burnouts, It shouldnt need it. we are looking at 180hp or less. Maybe just a spin to clean them. But it should hold for my application.

 

I didn't know that was available. I need to check on the Eaton and see if they offer a 2 series.