To all you "rear-end" gurus...take that however you want! I've done some searching on this site and others, and I still have some questions regarding the upgrade of my rear diff gears. This is my first automatic and I currently have 2.73's in my 94 Z, and I really want it to wake up some by installing 3.73's...since I don't do much in the way of Hiway or Interstate driving I'm not all that concerned with gas mileage...besides...this is my fun car.

Can I assume since it came with 2.73's that my car has a "series 2" carrier? I'm not as familiar with early 4th gens, but what type of limited slip diff if any did these cars come with...Eaton, Auburn or some other brand? As far as replacement gears...which brand is overall the best to go with considering that this is just a street car with the rare trip to the drag strip...Richmond, Mosier, etc.? Also...are the newer diff covers with support studs worth the money in helping reduce deflection of the gears/bearings?

Thanks for any help or advice!!

 

3.73 is a good gear for an auto car, will really wake it up, I think you have a 3 series carrier but i could be wrong on that, there are a few different carriers that were used, there is an auburn, thorsen or toresen or somethin like that, and i think one other, they should all be able to take 3.73's, GM gears are wat i use, there about the only ones ive heard of going in and not making noise after install

 

It is a 2 series carrier.

Should be an auburn if it is a posi.

I have always just used good used GM gears. However if you do not change carriers, you will need to run a thicker gear. I wouldnt use one of the spacers.

IMHO, I would not waste the money on one of those covers. Do they help? yes. But you are putting money in an overall weak rearend. Save the money and put it elsewhere.

 

^^^ agree.
2.73s' will only fit/work on a 2 series carrier.
98s' and earlier came with Auburn 'posi',99s' and later came with Torsen 'posi'. Nothing wrong with Auburns,smoother differential action around corners.
Aftermarket rearend studded covers is just 'insurance',but nothing has ever been proven.
All gearsets are good,provided they're set up correctly. Richmonds have a reputation for noise,but that could be how they were set up.
3.73s' for 2 series carrier are available from a large variety of sources.

 

I'm going to agree on the 2 above in the most part.
If stock you have a ''2'' series Auburn clutch type posi.
And any brand 3.73 gear for a 2 series carrier that is set up right will be good.

But IMHO the support cover is cheap and vital insurance. It keeps the rear from trying to spit the gears out the back under high stress times.
Another is get a RayTec solid shim to replace the crush sleeve upon reassembly.
With these added strength items an AUTO trans car can get into the low 11s on sticky tires without breaking.

 

Hey...thanks to those of you who took the time to help a fellow enthusiast out. I've never owned an automatic car, and I didn't think I'd like it all that much, but I'm finding that it has its benefits. However, these 2.73's are annoying and since I don't travel the highways and interstates with this car, I see no benefit to the 2.73 gearing. It's like having a Lamborghini with a four banger in it, all the show and none of the go.

Thanks also for the info and opinions on my initial questions, I just wish the "try before you buy" kind of option was available because I keep wondering if simply moving up to the 4.10's might not be a better idea. Time will tell which direction I go. Thanks again!

 

1. Carrier is a 2-series.
2. Diff is an Auburn "cone" type.
3. Richmonds are noisy, Motives are quiet.

I would upgrade to the newer Torsen diff, as the stock Auburn doesn't handle abuse well IMO. As for fuel consumption, I don't remember the 3.73s being bad at all. Of course, gas was selling for half of what it does now, so it may be that I just didn't care if I got miserable mileage. The 10-bolt can hold up surprisingly well behind an auto. I remember an article in GMHTP years ago where an LS1 car went 10.98 through an auto and a 3.73-geared 10-bolt.