Well while I was putting in my new 1700 transmission last night I noticed something peculiar when I removed my drive shaft on my 91 GTA. When I spun the yoke on the rearend the wheels rotated in different directions. So I am assuming the posi is shot. Am I correct to assume this? I have not done any one leggeres one the street or at the track. I was at the track 2 weeks ago and made four runs with no problems. I would appreciate any comment before I commit to dropping anothe garnd or two for a new rear end. Thanks

 

i think all these quick check like that are meaningless. do a burn out and see, pull the cover and inspect it

 

I agree, the only check that has meaning is to take off the cover and look. You may discover the car doesn't have posi at all.

Have you changed the fluid lately? Then you need to pop the cover anyway.

 

Well I know for a fact my car has a posi. It is a 91 GTA 350. I am the second owner with all the paper work and reciepts. I also serviced the differential last summer and replaced the crush sleave and pinion seal. It was at this time I think I remeber the wheels spinning in the same direction. I think the posi is shot, It just amazes me at how easily it spins the wheels in the oppostie direction.

 

Second owner and paperwork is useless information. There are countless posts from people on this board who have all that same stuff and thin kthey have one hting, but when they take off the cover and look, the reality is something other than what the "paperworK" or even the rear end code says.

Also, if it has the Eaton Gov-lock posi, it won't lock unless the speed difference between the axles is like 100 RPM or some such. Those aren't stock in these cars, but that doesn't mean there's not one in there, they bolt right in.

So did you see clutches in the carrier when you were working on it? Is it really a posi, or is it just a "paperwork" posi?

 

I saw the clutches. The whole reason I did the service was I noticed a groaning from the rear end while doing low speed sharp turns, like pulling into parking spaces. When I did the service I drained the diff case and the oil was dark but it was not gray. I then proceeded to rinse the case with brake cleaner and then blow it out with an air nozzle. I then refilled it with Mobile 1 gear oil and GM additive I got from the dealer. This fixed the groan. When I inspected the clutches I could still see fibirous clutch material. I know that does not mean much, but I do not know how else to tell if the posi is good by visual inspection.

 

That would be a posi for sure.

Sounds to me like it may be worn out. All it does is to "clutch" the axle to the carrier, which forces the axle to rotate at carrier speed unless there's enough torque available to make it turn at some other speed. Obviously the carrier can't rotate both ways at the same time, so the posi clutches should not allow the axles to do so either (unless it's a Gov-lock).

Bummer dude....

 

Well I am probably about to sound like an idiot, but here goes. I inspected my posi a little more tonite and found the following. If you rotate a wheel the other wheel turns in the SAME direction, but if you rotate the yoke the wheels turn in OPPOSITE directions. I am thinking this maybe OK and I am just a moron. Now can someone explain why that happens. Thanks for all the help to this point. That is why I like this board. everybody is willing to help.

 

that or you never had a posi, not puttin it down, i wish i had one...

 

Put some fresh gear oil and posi addditve and take it for another test.