Pele

iTrader: (28)

So I'm searcing for a 1999+ Miata Torsen differential... It'll bolt into my SE axle housing and it has 4.3:1 gears to boot...

I found one for SIGNIFIGANTLY less than the cost of others... (Most range from about $1000 to $400... This one was $250.)

The comments were as follows:

1999
Carrier
Mazda Miata MX5
PIG ONLY,MT5 LOCKING,WO ABS

What's "PIG ONLY"? Does that mean without the rear cover? Cool... I'm good with that. It'll be going in the SE axle housing, so no problem...

If it's just the front housing, no ring, pinion, or differential, I'm gonna be pissed... Well, not really, but bummer, cause that's a good price.

peejay

Pig is slang for centersection, third member, dropout...

I don't know what you mean by "rear cover". If you mean the case that the dropout bolts to (on the Miata it's just an aluminum dealy with some wings for the diff mounts) then yes, that would not be included.

vipernicus42

iTrader: (4)

What they call the pig, we call the pumpkin.

Jon

Pele

iTrader: (28)

By rear cover I mean back sectional thingy...

There's the cone shaped housing, that I assume is the pig or pumpkin that contains the pinion and stuff like so:



(Stolen Images, Not responsible for content.)

Then there's a cover that goes over it all. The CV halfshafts go into it. I wouldnt need it because that'd be replaced by my solid axle. I guess everything from the arrow numbered 11 downwards on the 2nd pic would count as rear cover on an IRS differential...

I guess I was thinking of an axle like the 1986 Camaro I've seen taken apart where the pumpkin and axle is one piece and there's a stamped steel cover over the back end, when I said "Rear cover"... Bad terminoligy, My mistake.

GavinJuice

So the pumpkin from a 99 miata wil replace the factory GSL-SE with no probs, and use existing axles?

Pele

iTrader: (28)

1994+ Miata pumpkin will replace the pumpkin in a disc axle 84-85 RX-7.

There are a few reasons to do this.

Torsen Diff. Only available on the M or Touring packages. The only definitive way of knowing this is to look at the diff... Either remove the fill and drain plugs and see the Torsen gears, or remove both halfshafts... If you can see straight through, it's a Torsen. If there's a bar, it's an open or clutch type differential.

1994-1997 had 4.10:1 rear end gears.

99+'s had a 4.30:1 rear end.

(What happened in 1998?)

Pele

iTrader: (28)

Ahahahaha!!!!! It's on it's way!!!!

peejay

Sure, if you actually *want* a Torsen diff...

To be fair, the pumpkin will fit in any '79-85 RX-7 as well as any RX-3SP.
The *differential* will only work in '84-85 models. (As well as '86-91 N/A)

Pele

iTrader: (28)

Where wouldnt you want a Torsen Diff? The only bad points about them are cost... (Taken care of by finding an incomplete unit like I did.) and the fact that if you have absolutely ZERO traction on one wheel, it acts like an open diff...

The last one I can't see myself having... I think I'll keep all four wheels on the ground on an auto cross or road race track, and if stuck on ice, simply apply the brake a bit ... I believe the brake application method is stolen from a Land Rover or Hummer manual...

This car will not be built for drag racing.

peejay

It's a trick from the HMMWV, and they had problems with snapping axles when doing it. (Is what I'm told. Some part of my brain is triggering "HMMWV had inboard mounted brakes" which would seem to preclude that, but on the other hand maybe the "fix" for that problem was inboard mounting the brakes)

I've heard of Quaifes wearing out in as little as a couple hundred miles. You can't rebuild one.

But hell, for the price you're paying, why not.

Pele

iTrader: (28)

I thought a Torsen diff doesn't have wear components like a clutch type?

Well thats a ****** buzzkill... But on the bright side, I still get my 4.3:1 rear end gears... They go for a couple hundred, don't they? So I get my money's worth.

BTW, is there any way to tell if it's worn out without actually driving on it?

peejay

Torsens work off of the worm gear principle. You can easily use a worm gear to drive another gear but it's very hard to use a normal type gear to drive a worm gear. This effect is due to the extreme sliding/wiping involved with a worm gear. When there's little torque disparity between the two wheels and/or when the torque load is light, the diff easily allows the axles to turn at different speeds. When there is a heavy torque bias from one axle to another, the worm gears in the diff *on the side that can accept the torque* bind up and most of the torque goes to that wheel. The diff still does work off of friction, and so the diffs can wear out, only in this case it's the internal GEARS that wear.

Pele

iTrader: (28)

So do I have to scope it out with a feeler gauge or microscope or soemthing or will I just be able to look at the Torsen's worm gears and tell if it's worn out?

BTW, there's edits to my spline thread that probably should be linked to this one.