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I have a question about posi-traction. I have a 46 1/2 ton with a open drive 12 bolt posi-traction rear end. When I back out of the dive way or make a turn it really clunks. Is this normal? I hate it. When I am driving down the road it is fine, no noise. any suggestions?thanks for any advice.
John

It will probly always make some noise but they can be realy bad if you don't use the propper lube.

Did you add the additive ? You need one bottle of positrac differential additive.I buy mine at the local gm dealer.It should help with the friction problem.

The newer gm locker rearends tend to be noiser and is supose to be normal.

After adding the additive, drive the truck in some slow figure 8's to work it into the clutch plates well. Brian

thanks, I will give the lube and addidive a try.
John

Checked the fluid, rear end is shot! Bits of metal, broken teeth, Oh well, I was looking for somthing to do on the weekends anyway!
John

Hay John is this a car or truck 12 bolt. I have a 12 bolt posi with 3.73 from a 67 chevelle. Didn't realy want to get rid of it but my truck needs money.

Grant,
Its from a truck, at least it has six lug bolt pattern. Im not sure I even want a posi, This one was in the truck when I baught it. Its kind of noisy and probably alot more expensive too fix or replace. I want to keep the six lug bolt pattern more than I want a posi-traction.
John

Some locking differentials work with a kind of ratchet action,and these are noisy by nature. Their popularity is from their very strong and positive function. It should be relatively easy to convert to a different kind of "limited slip". I wouldn't give up on posi-they're always a good thing. (In my opinion.) Like Heavyhauler,Tim and Roy said,it probably is a posi,I'm just suggesting it could be an actual "Detroit Locker,in which case there's not much you can do to make it quieter. Send some pics of the gear case if you open it up,that'll show us what it is.
Speed

My '63 3/4 ton has a "no-spin" detroit diff. Is this an early model "detroit Locker" like what the jeep dudes use nowadays and do I also need posi traction lube additives for the friction thing? I am hopleslessly without a clue!

Thanks for the info, the only number I can find is k292 on the bottom right hand side. I will take some pics.
John

Truckstein
No if your rear is truley a locker you don't need the additive. Limmited slip as called chevy and ford, or posi traction as called by mopar, and has become the common discriptive name use cluches. where as alocker is a ratchet system.

john,i would check and see how much it will cost to rebuild the rearend you got.Heck,it's already set up and in the truck.You might find it reasonable.

The additive helps reduce the friction on the clutches in the posi unit.

Iam looking on e-bay for a replacement also, swap meets. I will also look into a rebuild.
thanks,
John

Might not be a bad idea to make it known in the 4WD crowd that your axle is going up for sale. If it's in good shape you can probably get enough out of it to at least pay part of the new axle purchase,shipping or installation.
Speed

Thanks for the knowledge HevyHauler