A 1997 Camaro Z28 came with a 10 bolt, 7 1/2" rear, with 28 spline axles, an Auburn Posi, and 3.23 gears for an automatic, and 3.42 gears for a manual. Is all this info correct? Thanks!

 

Some of the auto cars came with 2.73 gears. And gm doesn't put an auburn posi in from the factory at least I have never heard of them.

 

I thought some of the 6-speed cars have 3.73 gears...

The POSI unit they use is a Zexel-Torsen.

Yes, the spline count is 28.

 

GM also used the eaton, and auburn. My 87 GTA had a auburn in it, and I just sold a auburn out of a 95 T/A.

 

Well, I guess I have to correct myself then, I THOUGHT the Zexel was the only posi they used in 4th gen's.

I did know that they used the Eaton in the late 80's, but I didn't know of it in f-bodies. Interesting.....

Anyone have any solid info on the 4th gen gear ratios?

 

AFAIK, the M6's got 3.42's ONLY from 94 on. 93 had a different ratio because of the different ratio in the tranny, can't remember which.

A4's come with 2.73 unless you get the performance axle ratio (3.23).

All are 28 spline, 7 5/8", 10-bolt rears. Traction control equipped cars come with ABS reluctors at each rear rotor and two rubber brake lines (4 channel ABS), otherwise there is a single reluctor in the pumpkin and a single brake line (3 channel ABS).

Earlier models got the Auburn Posi. 99 (IIRC) was the first year for the Zexel Torsen posi although some Firehawks and SS's got an upgraded Auburn if the person paid for it. I didn't, I don't like spending money on 10-bolts.

LS1 cars (98+) come with a different rear brake design that utilizes a drum-in-hat style emergency brake. Because of this, I believe ALL 98+ rear axles have a DRUM brake mounting flange on them. 93-97 cars utilize brakes which are functionally identical to those found on 89-92 cars and have the same flange pattern and backing plates.

I don't believe any 98+ cars came with drum brakes, not even the V6 cars. For 93-97 it seemed to depend on engine; V6s got drum brakes and V8s got disc brakes. It's possible there was an upgrade option on the V6 but I don't know for sure.

I also wanted to add that I have no data on the axle ratios for V6 cars.

 

93 M6 cars had 3.23s.

The Torsen was an option in SS and Firehawk models til the LS1 models, then they switched to Auburns. My SS came with the Torsen in '97

98-up LS1 cars don't use a drum brake housing; the housing is identical to 93-97, but the axles in traction control cars (maybe all 98-up) are slightly longer, or the c-clip location was changed slightly(either way, a non traction control axle won't fit a traction control rear). The only difference in the housings themselves is 3 or 4 channel ABS: 3 channel the sensor goes into the top of the housing, instead of on the backing plates like a 4 channel.

Some 3800V6 cars had discs in 97/97...this would apply only to the RS package cars though.