fast112

i have an 89 iroc-z with the 9 bolt with 373 rear gears, previous owner told me it was full posi, but i've done a few holeshots and 3/4 of them were full posi marks but there were a few where it was one wheel wonder, whats the difference between a stock limited slip rear, and a full posi unit, and where might i find a full posi unit for the 9 bolt rears?

DJP87Z28

Nothing but your wording....its a LIMITED SLIP

Air_Adam

Posi = Limitted Slip

fast112

so is it normal to have only 1 wheel spin sometimes? or does that mean that something in the rear is worn out.

Shagwell

One wheel spins sometimes happen with clutch type posi/ls units. Yes, it is usually a sign of wear. - Another thing, if it's a 9-bolt it could be a 3.70, but not a 3.73. No major difference(.03 of a driveshaft rotation), but that's the available ratio.

Frank89IROC

My 89 IROC came stock with the 9 bolt posi. Both wheels always spun on take off.

4ormula

with my 89 formula 350,when I stuff the pedal both wheels spin,the 9 bolt 327 gear is awesome. Maybe sounds like something is worn or tires. I have been looking at Diff solutions web site to upgrage to a different gear ration and add a stud girdle since I just rebuilt motor this spring.
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worn or tired in the rear end ,not tires cant spell correctly tonight sorry

Iroc_man

the dude who sold it to you is a 'er, he dosent know much obviously. by a "full posi" you must be talking about a mini spool. where the tires ALWAYS spin at the same time. a limited slip is much better.

1991L98G92

Posi-traction was a trade mark of GM, Ford was Traction-Lok, Chrysler was something else. You also have the Detroit Locker, which has no slip around corners. Limited Slip is the generic term. But everybody knows and uses the word "posi" to mean both wheels spin. And I still find people who call/think a standard differential is a "limited slip". Just like Channel Lock pliers or Vise Grips. May not be made by Channel Lock or Vise Grip, but everybody uses that name. I have actually seen a wrench other than an adjustable open end, with the name of Crescent on it, so there is a posibility that there is such a thing as a metric Crescent wrench.

If one wheel spins under acceleration and the other one doesn't, and it is a limited slip type, then, yes, you do have a problem.

87IROCZ350TPI

Not that it matters, But I came across a site that offers 3.73's for the 9-bolt. I don't know if that's typical, but they carried them.

scuzz

Does anyone know of a parts source for the 9 bolt? I need to go through mine. It has a little slack, and I thought I'd check the "posi" out also.
Thanks

87IROCZ350TPI

Ratech seems to be a good source for 9-bolt parts. Ratech Mfg On-Line Store
Another one that I have seen on this forum is www.diffsolutions.com.