Hello, I've read through the threads and can't find the answer. I'm getting mixed signs here. I have a 72 Riviera with the conventional 12 bolt 9-3/8 rear. I took this tag off of it so I figured I had a Posi. But when I do that wheel spin test the heels turn in opposite directions. Granted they are hard to turn (which I read could be a Posi thing) but never the less they still spin opposite. I cant find any ID numbers on the axel tubes.
72STAGE1, thank you. So what's with that wheel spinning stuff? Is that just one of those old tricks that's not really backed up? Do you know what this is by any chance? It's on the passenger side of the axel tube.
No MAX track. Car is not drive able right now. The tag made me think it was Posi but that wheel spinning in opposite direction threw me off.
Okay fellas thanks for the help. So I was looking around and found the code. My 71 shop manual states the code is on top of axel on passenger side. I ended up finding the code on both the 71 and 72 on the passenger side axel housing facing the front of the car. My 71 had UA P 1293 and the 72 had QA 0096. A quick look on the ROA website showed that QA is for a locked differential with 3.42 gears. I could not find UA P. So the code along with the tag confirmed that it is the Posi I thought it was. Thanks for the input. I always heard that the wheel spin test was the way to find out but I guess that is false. Well one website said it would spin the opposite direction but would be tough and this was true. Thanks to all those who gave their input.
A clutch type "posi" carrier still has spider gears. It's normal operation for the tires to spin in opposite directions if the trans is in park. There should be a moderate drag though..
Yes there was drag, like I said you read so much stuff on the internet and it confuses the heck out of you. But from what I've read here and then obviously the ID stamp on the axel and tag on the diff I'm sure I got me a Posi. Thanks all.
Can someone esplain how a dash mounted switch can activate was happening in axle.. "max trac"?. A downshift?
Max Trac has a great description in the shop Manual . A quick description is it has a computer , a sensor in the LF wheel and a sensor on the Speedo gear on the transmission . What it did was sense when the front wheel and the rear wheels spun at a different speed . When it did sense the discrepency the computer woud short out the distributor point to slow the engine down . Sort of the first generation Traction Control .
Why not just drop the cover & change the lube then you will know the truth..... Added bonus you will the know how old the new lube is......
Yup you have a posi. But to be clear, remove the cover wipe the loose clutch material out of the housing, re-install cover and add fresh oil with friction modifier. Not sure why others are fascinated with seeing pictures, but sure take pictures. Fat chance the clutches are worn with this set up. My car has 100k miles with the same clutches (technically not original miles) I only needed a small shim to get things to spec. Even loose (with out shim) when force was applied both tires spun.
You already got good answers and have figured out that it's a posi, but I just wanted to add to what Bill said: I have read that if a posi isn't working right, then the wheels will turn opposite when you do the spin test. So that seems to be the case here. My car's wheels spin opposite too. I haven't opened the pumpkin yet to verify that it's an open rear, so I am crossing my fingers hoping that my car also has a posi that isn't working properly. But in my case, it's probably as the Ancient Aliens guy would say: I'm not saying it's an open rear end But it's an open rear end.
