Chev truck question

[notfarnow]

I'm helping a friend swap out the rear end in his 95 Chev half ton this weekend. He bought a used one at a local wrecking yard, and paid an extra $100 for a posi track. He dropped it off in my garage last night, and it looks exactly like his old one (non-posi). I've had trouble with the wrecking yard he used a couple times, and wouldn't be surprised if it's just a regular rear end. What's the easiest way to tell the difference?

[Rot 911]

If the axels are still in turn one. Posi the axels both turn the same direction. Non-posi, turn in opposite directions.

[singpilot]

I would think one of the identification marks on the pumpkin would ID it as a posi. Absolute ID would be to remove the rear cover (messy, except that you get to change the fluid), and if there are more than a ring and pinion in there, it's a posi. The oil that goes back in might be different if it is. GM service rep (if you happen to get a helpful one) would probably tell you both things to look for.

[notfarnow]

Originally posted by Kurt V
If the axels are still in turn one. Posi the axels both turn the same direction. Non-posi, turn in opposite directions.

Well, I tried that, and they turned in opposite directions. Apperently, the wrecking yard told him that this rule of thumb wasn't true on these trucks. Didn't make sense to me.

[legion]

Sound like a bunch of scheisters to me.

[singpilot]

I know the newer posi's are different. The old rule of axel turning might not work. Try calling a GM truck service department, and see if you can talk to someone that could ID the number or code.

Especially if you bought it in NB, it probably IS a posi. Up there, would almost be required for winter work. The fact that you paid extra for it makes it serious if it is in fact not.

[notfarnow]

Originally posted by legion
Sound like a bunch of scheisters to me.

That's what I thought too. And the effen thing left a great big puddle of gear oil on my garage floor.

Their explanation was that it'll turn like a regular differential until one side starts to spin. I dunno. The same folks sold me a transmission once, and when I got it installed 1st gear would grind... they tried to tell me it had a non-synchro 1st.

[Rot 911]

Originally posted by singpilot
I know the newer posi's are different. The old rule of axel turning might not work. Try calling a GM truck service department, and see if you can talk to someone that could ID the number or code.

True, some of the newer posi's do require that the axels turn at a certain speed before they lock up.

[singpilot]

Originally posted by Kurt V
True, some of the newer posi's do require that the axels turn at a certain speed before they lock up.

Kurt, that's what I meant. It involves clutches that take some movement to work properly. Is also the reason for the special oil for posi's.

[notfarnow]

Thanks guys... looks like we'll have to call the GM stealership. I certainly won't put it in till we know for sure.

I just figured there might be an easy identifier.

[kumma]

Crack it open and look at the diff, if it looks like a cookoo clock you got the gov lock if not its open. You shoud do that anyways just for piece of mind.

[notfarnow]

Thanks for the help on this folks, we took the cover off and it was a posi. Other than that, there was no way to tell from the outside.

Apparently the old rule of thumb about both axles turning in the same direction doesn't apply anymore. They turned in opposite directions on this one, probably until the clutches engaged because of slip.

Anyway, we got the thing in. It was a great upgrade for the $100 difference, considering he had to change it anyway. It was a straight bolt-in job.

Thanks again!

[legion]

Glad to hear that it worked out and that you got what you paid for!

[notfarnow]

Thanks,

I still wasn't overly impressed. The whole thing was pretty messy, several bolts were seized on, and the U joint had been cut off with a torch.

The biggest PITA was the fill plug. Once we got the rear end bolted in, we realized the fill plug was badly seized. We probably spent 4 hours fighting it.

I think a decent wrecking yard would at least wd-40 stuff like that before they send it out. Really good ones will make sure nothing is seized. If it had been my money, I would have been pi$$ed, and probably wouldn't have taken it in the first place.

I did loose time though... instead of it being a 1 day project, it tied up me & my garage for 3 days. Can't complain too much, I helped out a buddy who has saved the day on numerous occasions. He's a carpenter/renovator, and I have a 150 yr old house. It was nice to pay him back, and he was really happy with the outcome.

[singpilot]

Glad to hear it worked out. I too had heard the old rule was not necessarily true as well.

A favor done like that will come back in spades some day when you really need it.

[legion]

Yes, you will need those favors when you do buy a Porsche...

[notfarnow]

Actually, once we got his truck back together, we used it to pick up a 2.0 911 longblock. That kinda sorta makes me a Porsche owner, doesn't it?

Singpilot, I've been meaning to ask you to post a pic of your sailboat, but I didn't want to hijack another thread. It's a Hunter, isn't it? I'm in the process of putting my Chrysler 22 away for the winter.

[singpilot]

P.S. That IS a California winter out on the mooring at Catalina.

[David]

This is good to know. I was pissed the other day when I had my 2001 silverado on jack stands and I noticed the wheels turned opposite. It's supposed to have posi... now I guess it does.

[notfarnow]

Sweet! A friend of mine bought a Cal 9.2 this summer, and sailed it up from NY city. I hopped aboard in Newport, RI. We skulked about in Newport for a few days and moored beside a beautiful Hunter, until the weather changed in our favor. The Hunter had 5-6 people aboard that whole weekend, and we certainly resented their comfort & style. They are a beautifully finished boat.