Gearbox Identification
There have been at least 7 different GT-Four gearboxes, possibly more. So how do you tell them apart if you find one at a wrecker? Toyota don't stamp their gearboxes with the type number, so it isn't easy.
ST165
E50F1 Only fitted to 86-87 Japan spec models. No viscous coupling, locking centre diff. Not a good performance choice. Has a large pneumatic actuator fitted to the transfer.
E50F2 Fitted to all 87-89 models (post build number -0002274). Introduces viscous coupling. Available with 4.285 final drive (Japan) or 3.933 (export). These have a pressed steel clutch fork.
ST185
E150F Normal early ST185 gearbox. Identified by the cast steel clutch fork.
E151F RC gearbox. Improved dual cone synchros. Fitted with 3.933 final drive in all homologation models. This gearbox may have also been fitted to other post 91 facelift ST185's. Not sure on their specification though.
E152F I believe that this is the gearbox from the Japan only GT-Four Rally model. This has different ratios.
I don't know how to identify the different ST185 gearboxes! Without stamped markings, they all look the same.
ST205
E154F Revised gearbox with different ratios for better accellaration. Dual cone synchros are used as per the RC gearbox. The fwd selector lever has been removed. Obviously this is the gearbox to buy! Easily identified by the lack of fwd selector lever and the small rubber vent below the shift fork.
ST205 gearbox from the rear. The fwd lever is to the right of the transfer on a ST185 gearbox. | The front view showing the small rubber vent below the shift fork boot. |
Ratios: (Japan spec)
1st | 2nd | 3rd | 4th | 5th | Reverse | Final Drive | |
ST165 | 3.583 | 2.045 | 1.333 | 0.972 | 0.731 | 3.583 | 4.285 |
ST185 | 3.384 | 1.913 | 1.333 | 0.972 | 0.731 | 3.545 | 4.285 |
ST185 RC | 3.583 | 2.045 | 1.333 | 0.972 | 0.731 | 3.545 | 3.933 |
ST185 Rally | 3.230 | 2.142 | 1.518 | 1.258 | 0.731 | 3.545 | 4.285 |
ST205 | 3.384 | 1.913 | 1.258 | 0.918 | 0.731 | 3.545 | 4.285 |
MR2 Turbo | 3.230 | 1.913 | 1.258 | 0.918 | 0.731 | 3.545 | 4.285 |
These numbers are from the Hyperrev so export and US spec models may differ. The RC gearbox ratios are what have been found in two RC gearboxes locally, ratios may vary.