A technical write up of Turbosupras on the Toyota R154.
The Toyota R154 Specs
Toyota Motor Corporation’s R series is a family of 5-speed RWD/4WD transmissions found in the MKIII Supra Turbo, Toyota Crown, Toyota Chaser Tourer V, Toyota Mark II Tourer V, Toyota Cresta Tourer V, and Toyota Soarer (turbo) up to 2004.
The R154 is made by Toyota, Japan. As with most Toyota driveline components, the R154 has quality of design and performance. Unfortunately as always seems to be the case with modern technology, their is always a downside.
The R154 is a conventional 5-speed gearbox, with five forward gears and a straight-cut reverse gear. The reason for the strength of the gearbox is clear to see even by the naked eye. The external housing and the gears themselves are credibly sized for a performance-oriented gearbox.
The downside of R154 is the first gear thrust washer. This part is prone to breakdown if the box is maltreated. In most known cases of failure are results of the following action:
- abuse or misuse of the gearbox
- when the gearbox is used with a high-clamp and/or button clutch
- big-horsepower applications
If this dilemma may arise, The easiest fix is to lighten up on the gearbox and treat it with respect. For gearbox owners with less self-control, the best solution is to have the gearbox broken down and reassembled with a new thrust washer made of chromoly for added strength.
The part itself is quite inexpensive. Turbosupras team researched the price in the market and its playing around AUD$26.50, however the damage it can cause in the event of failure is quite humbling. The first gear bearing takes the brunt of this failure due to being located in front of the thrust washer.
In more severe breakdown, or if the car continues to be driven after a failure, one or more of the gears turbosupras advise you to replaced the gear. First gear alone has been priced at AUD$550. Certainly price is pretty stiff.
The ideal solution is to replace the R154 with a V16x gearbox from a Mk4 Supra. These are much stronger and more widely proven behind big-horsepower 2JZ engine combinations.
Manual Transmission Specifications
Gear Ratio Km Per 1000rpm
First 3.251 9.6
Second 1.955 16.0
Third 1.310 24.0
Fourth 1.000 31.4
Fifth 0.753 41.7
Final Drive 3.727 (Mechanical LSD)
Lubricant Capacity 3 Litres
Oil Specifications 80W-90 GL4 or 5 Gear Oil
Dry Weight 46kg
- Length – Bell housing to Out put shaft
- Length – Bell housing to End case
- Length – Bell housing to Centre of Shifter
- Width – Bell housing
- Width – Gear Case (maximum)
- Height – Bell housing
- Height – Gear Case (maximum)
- Input Shaft OD 30mm
- Drive Plate Diameter 245mm
- Drive plate surface area 40mm