rear dif gears

cuel

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#2
4.30:1 Some open, some LSD in the n/a's
3.9x:1 Came in the earlier(?) turbo models
 

Nick M

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#4
The term you are looking for is taller.

It is an 8.0" diff. Check Summit racing for a set from Richmond or another reputable gear cutter. I am not positive on the directness of the change over.
 

Dan_Gyoba

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#5
Toyota used the 8" ring gear in a few vehicles, including (IIRC) some of the diesel Land Cruisers. Those will have taller gears in 'em.

The trick there will be getting one fo the 4 pinion ring gears. You can keep the pinion and LSD setup that's in your current diff so long as you get the 4 pinion ring gear.

Putting that together is something that's beyond what I'd want to do, but it could be done.
 

prsrcokr

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#6
Lower=shorter, taller=higher they're used interchangibly. The only ratios I'm aware of in the mk3 were 3.73, 3.91, 4.10, 4.30. I'd never thought about the Landcruiser gears, wonder if they're interchangible.

Whats the reasoning for looking for something taller, mpg, top speed?
 

IwantMKIII

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#7
don't really see the point of this....3.73 is short enough as it is and for higher power cars 1st and 2nd become useless
 

Dan_Gyoba

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#8
I think the point is that 3.73 is short, and that 1st gear does become useless.

With a taller diff, this extends first gear, so that it starts becoming useful again. Or, it could be used to swap in a V160 6 speed transmission with a JZ block.

It extends top speed on the car for those who are gear limited on their top speeds (Not that that is going to happen this side of 500 rwhp, IMO) but mostly, it just gives you back first and second.

The quick way to check for the right (8") ring gear is on the vehicle data tag. The ones that work will be Gxx4 and Gxx5. These are the 8" ring gear with a 4 pinion setup. These ring gears and pinions can be fit into the Supra's diff case, and you'll get the gear ratio that goes with it. If it's a 4 for the last digit, it's a 4 pinion open, and if it's a 5 then it's a 4 pinion limited slip. Obviously the LSD one will be an easier choice, since you won't need to swap in the Supra's LSD section.

Side note for those looking for lower (drag) gears. All Canadian model MA70 NAs came with a 4.300:1 limited slip, so the carrier from one of these will work perfectly, and give you the lower gears.

I used to have a link with what the xx numbers mean in terms of gear ratio, but it's a dead link now.
 

Nick M

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#9
Transfercase yes, diff no. You can call it sway bar link for all I care.

A higher gear numerically is a shorter gear. A lower gear is taller.
 

annoyingrob

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#10
Jawsgear can make you a 3.54 ring and pinion that will bolt into your pumpkin, and use your existing LSD. They were about $200 for the pair last time I checked.

There is also a SUPER SUPER SUPER rare 3.22 diff on some (maybe all) Turbo A Supras (which there are only 500 in the world).

I've heard people talk about truck gears, but nobody has bothered to test fit them.
 

Kai

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#11
I was thinking about this myself - Marlin Crawler might be able to help as they stock a lot of diffs/gear selections for most Toyota Trucks...