posi check

[davidh]

I had a guy who had a posi in a older 64 and He said the way to tell if it had one was put it in neutral jack up one wheel off the ground and try to turn the tire. If its got a posi it wont turn. He showed this, jacking up one side.

Does everyone agree with this? I'm going to a junkyard to look for a 6lug posi and I know most of the trucks are 60-66. Theres no buid sheet on the glove box of these and I'm not pulling every rear end cover off this guys place to look for one.
Is the method the best way to look for one? Thanks david

[65-72 chevytoys]

That is correct. If it is just an open diff. The wheel off the ground will rotate by independatly. Yes it is a method to tell. The best way is to verify by pulling the cover. But I agree I don't like being under junkyard vehicles at all.

[whatnow123]

Originally Posted by 65-72 chevytoys

That is correct. If it is just an open diff. The wheel off the ground will rotate by independatly. Yes it is a method to tell. The best way is to verify by pulling the cover. But I agree I don't like being under junkyard vehicles at all.

is this correct? I haven't driven my truck yet (bought it in boxes mostly), I had the rear axle off the ground, wheels turned in opposite directions, but if one tire is on the ground, the one off the ground won't turn.

What is going on with mine? Anyone know?

[CochinoFilipino]

I believe that is correct and that's how I'd do it.

But I wonder if this method could tell you anything about the condition of the posi unit. Even though you can't turn it by hand, it still might not leave two equal length black strpes?

Maybe someone can tell us how to test if the posi is still good. The only method I can think of is if the truck is powerful enough to roast two tires without using the brakes (since applying the brakes can have a posi effect itself).

[uncle]

Not true if the clutches are worn.

[hellrazrblade]

This should work, correct?: jack the rear end up (both tires)
if the tires rotate opposite, you're open (that's why you have to set the parking brake when you're rotating tires on a regular 2wd with an open diff - you'll rotate it off of the jack)
if the tires rotate together, you've got a posi

[jkade]

I just installed a eaton posi today and both axles turn the same way and before with the open they turned oppsite of each other. If you have a posi one should not turn if the other is on the ground. Don't hold me to this.

[GREASEMONKEY72]

with whats been said and if you want to check with a running car powerbrake it and if one tire spins its an open and if its an open other tires will spin oposite ways when you jack up both and spin one tire

[sixtysevengmc]

Originally Posted by GREASEMONKEY72

with whats been said and if you want to check with a running car powerbrake it and if one tire spins its an open

not nessesarly...as Uncle said,worn clutches in the diff will make a posi unit appear as if it were open.
I had this issue with my old 68 C10,468/th400 with a supposedly 12 bolt "posi".It would only spin one wheel (alot) no matter what,pulled it apart to install a locker and was surprised with a posi carrier