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Reverend Hillclimb
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Discussion Starter #1 (Edited)
Any experience with Gforce GSR/SR1/G101 transmissions?

As the title states, anyone have any experience with these? I know they are 4 speed dog box/nascar transmissions.
They are pretty cheap used and cheap to rebuild.
RTS transmissions already sells the adapter plate and spline for the 2jz. Figured someone knows a guy who knows a guy who has one or something

Any gforce experience would be helpful I guess.
 

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Supras with those trannies are few and far between. Maybe reach out to Craig Bush since he's had Gforce, as he recently mentioned in a strength of drivetrain thread still active here:

...my car has been original v160, GForce gf5r, brand new v160, rebuilt (after ONE half-mile event) brand new v160, th400, and now Grannas t56...
 

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Reverend Hillclimb
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Discussion Starter #3
Supras with those trannies are few and far between. Maybe reach out to Craig Bush since he's had Gforce, as he recently mentioned in a strength of drivetrain thread still active here:
Will do Nick, I honestly dont even care if its in a supra. Any experience is helpful.
Hard to find info on these anywhere really other than calling gforce, in which case I would rather have user input rather than vendor-level.
 

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Marvin,

Don't quote me on this, but member 220 may have a GForce in his highly modified MKII Celica Supra.


Ken.
 

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Unlimited Time Attack A70
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Marvin,

Don't quote me on this, but member 220 may have a GForce in his highly modified MKII Celica Supra.


Ken.
He actually has a R154 with a PGS dogbox gearset
 

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I have a GForce GSR in my mk3. I only recommend it for straight line racing and light street driving.
 

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The GForce transmissions are getting to be a popular option for dedicated drift cars, too. Easy to buy a used NASCAR box and put a 2JZ bell on it.

I haven't driven one on the street yet or in anger on a track so I don't have much to say first hand, aside from the fact that I have seen exactly zero street-driven cars equipped with one.
 

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Unlimited Time Attack A70
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The GForce transmissions are getting to be a popular option for dedicated drift cars, too. Easy to buy a used NASCAR box and put a 2JZ bell on it.

I haven't driven one on the street yet or in anger on a track so I don't have much to say first hand, aside from the fact that I have seen exactly zero street-driven cars equipped with one.
The t101a are quite popular and cheap used, only problem is they aren't that strong, especially for a high hp supra application. Not to mention they are a side shift tranny. The GSR Gforce on the other had is quite the piece of machinery, is center shift and can take 1000+hp without a problem. There is a few variants of the T101 that have stronger cuffs and cases making them suitable for 5-700hp range.

A GSR would be greatly suited for road racing, straight line and even street driving if you actually know how to shift it. Dogboxs like it hard and fast :agreed:
 

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Reverend Hillclimb
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Discussion Starter #12 (Edited)
So I found:
- bellhousing (no need to use factory v160 bellhousing) RTS sells this
- Throwout bearing - tilton 4000 series
- G101a box
- xcessive manufacturing seems to make a flywheel adapter for the 2jz to 7.25 clutches
- any 7.25" clutch with 1-1/8'' x 26 spline configuration - RAM, quartermaster, Tilton, ACE, and the list goes on - You can buy used nascar tilton triple disc clutches for sub $1000 in good condition.
- 32 spline yoke for output shaft- well you can find these all day - mark williams, spicer, strange, etc.

Custom items would be
- driveshaft - decent driveshaft shop can do this
- Shifter relocation - Gforce offers their "road race" shifter with chromoly shift rods, and you can just custom make a bracket to move it, but I know gforce offers different adapter plate sizes but unknown on the supra specific dimensions needed.
- Trans mount - easy for a competent fabricator

Now there is also the option of a t56 with straight cut gears or dog engagement.
I think all the above parts minus the bellhousing, mount, and shifter relocation would transfer over no? T56 is also 26 spline and I dont see why the clutch wouldnt work, maybe the throwout bearing would need to be a different part number but otherwise I dont see any issues?

If anyone is experience in general with transmission swaps etc, feel free to critique as I only obtained this through reading and the materials that cover this info are few and far between, so I have just deduced some of the info from reading alone, and I am sure there is a hiccup or two in what I said.

Nice thing is the g101 series are easy and cheap to rebuild (relatively), robust, and used nascar parts are abundant (clutches, gears, bearings, yokes, etc)
 
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