i really want to swap out gears to 3.73 on my firebird but have a series 2 carrier and series 3 can go for pretty cheap on ebay what is the torzion posi? and what is better the auburn or the eaton locker those are the three that are on ebay and i dont have money to buy a trutrac

 

A) which type of carrier does your car currently have? Torsen or Auburn?

B) there is no need to replace the carrier if you want to run 3.73's, unless you think your carrier is shot and you need a new one anyway .

C) it's hard to say which carrier is "better". The Auburns act much the same as the old clutch-type "posi-traction" diffs back in the day ... basically, just friction force holding the axles together, and it takes something like going around a corner to overcome that force and allow the axles to turn at a different speed. BUT, the Auburn (like the old posi) will eventually wear out. The Torsen uses a mysterious series of little worm gears inside! When one wheel starts to slip, I guess it tries to get the other wheel going?! The beauty is, there's nothing to wear out. The Torsens work until they break!

I "think" the Eaton units are basically a true "posi" in the sense that they use clutch packs to keep the axles turning together .

 

I can just throw a set of 3.73 on this carrier thats got 2.73 on it i dont undertand the reasoning behind the sereis 2 and series 3 carriers cause series 2 go dirt chea on abay and series 3 are around 100 bucks what is the difference between them? this is really bothering me i need to know

and i dont think an eaton locker uses clutch packs?

 

You can put 3.73's in a 2-series carrier, but you either have to buy 3.73's specifically make for a 2-series carrier, or you have to use a spacer to fill in the gap between the 2-series carrier and a 3-series ring gear.

Eaton makes a limited slip (posi) rear. Its got clutch packs. That is not a "locker".... that is something else.

 

are eaton lockers any good?

 

A "limited slip" differential, whether its a clutch type or a Torsen, will usually have a "gradual" enagement. Get on it hard, and the axles lock together, if there is any wheel slip. Get on it 1/2-way, and the axles will gradually lock together. A "locker" is a bit different.... there is no middle ground. Its either "on" or "off" (mostly locked, except when you turn a corner), which often results in a lot of chatter and a harsh, noisy, sudden engagement. You have to decide if you can live with something like an Eaton "Detroit Locker" on the street. They may be better suited for the track.

http://www.eaton.com/EatonCom/Produc...ials/index.htm

 

I live in nyc, lockers have a hard time in the inblocks constantly locking and unlocking(they get chewed up). They are also harder on your axles and carrier bearings. I like the eaton hd clutch style unit with carbon fiber plates and 400 lb springs. This is only my opinion!!!

Remember to only use regular (non synth oil) with all clutch/cone style diffs.