posi question

[Shimy87]

New issue....this year when I screw around a do a burnout 30% of the time only one tire spins?? Whats causing this 

[Steve Wood]

sounds like the posi needs to be rebuilt...clut ches are worn out, I would guess

[Shimy87]

Stupid question....is that a DIY job. I'll have to do a you tube search

[Steve Wood]

I did my own but you might be better off having a shop doing it if you don't have dial indicators, etc to check clearances with.  I just swapped  a new Eaton HD into mine but I had to shim it for clearance and such.  You tube will be better at explaining than me

[Scoobum]

I did my own but you might be better off having a shop doing it if you don't have dial indicators, etc to check clearances with.  I just swapped  a new Eaton HD into mine but I had to shim it for clearance and such.  You tube will be better at explaining than me

Steve...in theory...if you replace the shims the way they came out...should all not be well? What backlash did you set yours at? I had a Pro Stock drag racer set mine up...and he gave it a couple more thousands of an inch over stock.

[Pyro6]

In theory, if you're only replacing the clutches, reuse the shims in their same spot. If you're going to do side bearings, pinion bearing or housing change, the setup needs to be redone.

[Charlief1]

If I remember right, you don't need to pull the carrier to do the clutches.

[Shimy87]

I cant find any " how to" info for doing the clutches and I think that is all I need to do. Car only has 60000 on it. Dosent make any noises, just wont spin both tires every now and then.

[earlbrown]

If you use the posi additive, get rid of it and see if that fixes your issue.

And keep in mind if one tire has more traction than the other, you can still get 'right tire fire' even if everything is in spec.


The difference it takes to break the axles free from each other is only 60ft/# with a torque wrench hung on a lug stud.

[Shimy87]

Ive never had it apart or added anything. When it spins one its the left that spins.

[Just a Six?]

If I remember right, you don't need to pull the carrier to do the clutches.

I never did & the only hard part was removing & installing the Spring Clips. The rest is pretty simple just put them back in the same as they came out. Probably a Tech article on turbobuicks from the old days. I ordered mine thru Bill Savino way back then.
Make sure to add a drain plug in your cover so it's not so messy next time!

[Steve Wood]

Brad, I don't remember...I changed the bearings as well as I went to a 30 spline axle and unit

[earlbrown]

Ive never had it apart or added anything. When it spins one its the left that spins.

Now that's just odd.   Engine torque pushes down on the LR and tried to lift the RR.   Not to mention, the drivers side of the car is heavier.

[Shimy87]

I know. Last time it happened it left a strip 40 feet long and nothing on the pass side. I better take cover off and see whats going on in there. Cant be that complicated

[earlbrown]

Pulling the cover is easy enough.


Clean off the magnet and refill with non synthetic with NO posi additive.     Do a few figure 8's in a parking lot to coat the clutches with fresh jizz, then see if anything changes.

If you're lucky the rear end will chatter when making sharp turns.


Isn't your car fairly low mileage?