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I've got a 9" rear with a posi unit. at least that's what it was when I took the diff. case out of the housing...Now, after I put it back in, both axles seem to bolted in place, but when I spin the yoke, only the driver side tire spins. When I hold the yoke still, and spin either tire, the other does nothing. It acts like the passenger side axle just isn't inside the diff. case. While it was out, I put both axles in, and it worked great outside the housing. Also, the splines on both are fine, and the diff. gears are all fine too. Anyone had any experiences like this? Or have any ideas what's wrong with it? The car drove fine before I took the diff out, but the posi never did work before...help..?
 

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Something sounds a bit fishy....even an open will spin the other tire when you hold the pinion still and spin one tire...

Normally I'd ask if a friend switched axles on you and gave you two short axles...*G* There's a long and short axle for 9" rears...

Got no clues on this one....

What did you do to the rear while the center section was out..? Why is the rear end being serviced?
 
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no, the axles are different. the passenger is longer. Also, the reason I was taking it out was to replace it with a posi unit...I thought maybe the passenger side axle wasn't in the case, but then why would it spin true...did they make more than two axle sizes? maybe I've got the correct one on the Driver side but teh passenger side is a little shorter, but still longer than the driver? I've got no clue...Not an expert on it...
 
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Another idea, could it possibly be that I have one axle from a 9" (the driver side one) and one from an 8"? Would an 8" would be a little bit shorter?
 

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Did you fill the center section with the correct fluid after reinstalling it? I'm not an expert on this by any means, but when we put the posi in my car, we had to put in the correct fluid for the clutches to work. Could that be the problem?
 

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My recollection is that the 8" and 9" axles had the same offset but I haven't done a complete rear end job in nearly a decade (like swaps and narrowing and the like).

I would imagine you could stick a stiff tape measure down the tube and do some measuring from the spider gears out to the bearing area and compare to the axle. That may sound weird but it's likely what I would do if I wasn't sure. What happens if you spin the non-functional axle by hand? Do you see or hear anything out of the ordinary?

Guess I'm on a fishin' expedition here..*G*
 
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well, it must've just been one of those things. I pulled both axles out again, shined my little light down there, everthing looked ok. I put them back in and what do you know, it works fine...I dont know what happened before, why it didn't work right...ah well, i'm just tickled pink it's working right now. Also, it's not a limited slip, so I don't need any special oil/lube. Thanks for the help!
 
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