Ok....so I my axle seals finally failed. I blew a side gear shim and only had maybe 1 pint of fluid in my diff.

Replaced my bearings and seals no prob.

I went to get a new gear set from the dealership and they didnt fit.

This is what I have:
(1991 chevy camaro Z28 convertible)
26 spline axles
3.42 rear (41 teeth on the ring and 13 on the pinion)
open diff

They deal said I should have 28 spline axles with a posi rear.

My axle tube stamping reads (1st 3 letters): 6HT which denotes an 88 or an 89 with 2.73 posi.

Someone help!!!!!

Oh and one more wierd thing.....on the same side as my differential drain plug, I have a little plastic tube that fits into a little port on top of my diff.

What the hell is going on? Is that an ABS sensor port?

My camaro was built in 03 of 1991

The little plastic thing is a vent. Maybe the rear end has been changed in the last 14 years.

im just curious how you couldnt tell you had 3.42 and not 2.73's, thats a pretty big rpm difference while cruising

GM changed the spline counts around '88/'89. The early cars had 26-spline axles (like the G-body), so they used the same posi units and gearsets. After the G was disco'd, they switched to 28-spline axles. Sounds like a previous owner swapped the early rear in your car and re-used the original axles with a new gearset.

Cool....thanks for the info. Good to know I have a 3.42 rear for when I do buy a posi unit (thought I had a 2-series carrier).