I'm about to buy a 3.42 rear end that's supposed to be off a 1992 GTA.

It's disc with the finned calipers. He says it's 3.42 w/ Posi.

Is the ratio stamped in plain sight if I unbolt the cover?

Before I drive 2.5 hrs...Were all 91-92 3.42's Posi and can I tell just by spinning each wheel and seeing if the other turns?

I gotta make a quick move on this purchase.

Thank You,

Shawn

 

Pretty tough word there, to describe an option with.

Not necessarily; although to get that gear, it would have to have been a G92 stick car. A highly likely candidate.

Yes the ratio is in plain sight. 3.42 will be stamped 12:41 on the edge of the ring (41 / 12 = 3.41666666666666....) and will have .... {drum roll please} 41 teeth on the ring and 12 on the pinion. {cymbal crash please}

While you're checking the gear, just look at the carrier. It will look like these if it's a posi.



These are both Auburn POSs; the one on the left is a stock 2 series POS, the one on the right is a "high perf" 3 series POS. In the "window you will observe some plates and springs. If you don't see that, it's an open rear. If instead you see a couple of little weights on little shafts, it's an Eaton Gov-Lock. AFAIK that didn't come in those cars, but who knows what you might find in it after 20 years.

I would not mess with the stupid "turn the wheels" crap. LOOK AT THE PARTS. It's your money, you wouldn't go to the grocery store and pay some random price for some bag of groceries that you didn't even look inside and see what was there, just based on maybe squeezing the bag or something, would you? So why do people EVER think that's "a good idea" just because it's car parts instead of groceries?

Personally I'd buy it no matter what gears or posi it has, just for the brakes, if the price is right. THen I'd take out all that stock crap and put in an Eaton posi, the stock gears for my car (3.73), better axles, LCARBs, have the tubes welded up, put a girdle cover on it, and do everything else possible to upgrade it. Oh wait... can't, already did.

 

If you're swapping from drums to discs, you might wish to peruse the info below:

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

JamesC

 

for a quick check if you spin one axle and the both move in the same direction its posi, If you spin one side and the outher moves in opposite direction no posi or posi is broken.

 

Yes.

JamesC

 

Thanks for the info guys!

I'm looking for the best 3rd gen 3.42 rear end for my 91 Firebird...

The first time I talked to this guy he said it was in a 92 GTA 305tpi 5spd.
Talked to him a few days later to follow up and he said it was out of a 350 auto?
So now I'm questioning his integrity, but he did say to pop the cover off and check it myself for the gear ratio and posi. He actually encouraged me to.
He said it has the calipers with the big fins. He also has it advertised as a 3.42 Borg Warner w/alum. driveshaft.

So if all this is true regardless of what car it came out of, what does this confirm? Correct me where I'm wrong:

90-92 Disc have alum. PBR (finned) calipers and are all 10 bolts, which are the same as what all 1LE models used?

I should be looking for a tag with 2PN on it which would indicate 90-92 3.42 posi. according to this site: sethirdgen.org/reardata.htm

So if I see it stamped for 3.42, confirm posi, see the finned calipers, and find a tag with 2PN...can I assume that (unless modified) it's a 90-92 10 bolt Borg Warner 3 Series? That chart makes it look like 2PN is all I really need to find what I'm wanting.

One thing I have not been able to find in my research. Concerning the rear end...What's the difference between v6 3.42 & optional G92 3.42?

I'm thinking I should be looking for a 90-92 because they are all 28 spline? or just the V8's?

Thanks for bearing with me as I learn. I've read threads until I get a headache trying to learn.

-Shawn

 

1. All J65 89 9-bolts and J65 90-92 J65 10-bolts have 11.7" rotors and single-piston alum PBR calipers (the so-called 1LE's).

2. If you find a tag or axle tube markings, you'll be lucky. Best bet is to drop the cover and check the numbers on the ring and pinion. Check post #2 or the 10-Bolt FAQ for those numbers.

3. I wouldn't assume, I'd pull the cover for visual verification (if you purchase it, you'll want to change the fluid anyway).

4. a 3.42 is a 3.42.

5. All.

JamesC