At the beginning of Project 2JZ, it was decided to use an automatic transmission for cost reasons alone. Manual transmissions for a 2JZ are expensive and difficult to find. Also, both the V160 (Mk4 Supra 6-speed) and R154 (Mk3 Supra 5-speed) are too large to fit in a Mk2 transmission tunnel without extensive modifications, while the auto fit in without any problems.
However, I got lucky and found a 5-speed transmission from a non-turbo Mk4 that was within my budget. This is an updated version of the W58 found in the Mk2, so while the internals are slightly stronger (eg bigger input shaft bearing), it is externally almost identical to the original Mk2 transmission. This has obvious benefits - it allows me to use the factory transmission mounting points, and I don't need to get the tailshaft modified. And since it came from a Mk4 Supra, it has a bellhousing to suit the 2JZ block.
The first step was to test-fit the transmission and compare it to a standard Mk2 Supra. My friends developed a creative method for holding the transmission up while it was being bolted in. It involved a torque wrench and a length of rope, and it worked remarkably well!
From this we determined that the engine had to move back 50mm so the transmission mounting points would line up correctly. This meant the custom crossmember brackets had to be discarded and re-fabricated. So, the crossmember was pulled out again and sent off to a friend for modifications.
Here's some pics of the Landcruiser rubber mounting blocks, and the completed assembly ready to go back in the car.
While the crossmember was out of the car, I took the time to measure the overall dimensions and draw a rough sketch. You can see it here.
With everything lined up correctly, it was time to pull the transmission out again to allow the installation of the flywheel and clutch, and also to swap the shifter mechanism from a Mk2 Supra transmission. As you can see in these photos, the two boxes are practically identical but the shifters are very different!
Since the original transmission mounting points were used, the factory tailshaft was the correct length and could have been used as is. However, the relatively small universal joints were a slight concern considering the vastly increased torque loading they would be subjected to! I took it to a tailshaft specialist who recommended I use a Hilux tailshaft cut down to the same length as the Supra shaft. The design is very similar (two-piece with a centre bearing), but the Hilux universal joints are much larger.
The yoke is the same so it fits into the transmission with no modifications, however the diff flange bolt pattern is quite different as you can see in the pics below. The diff flange had to be made slightly larger in diameter to accommodate the larger PCD of the Hilux flange, and then it was simply re-drilled to match the Hilux shaft. After that was done, the whole thing bolted in like it came that way from the factory! Neat.
The final hurdle was the clutch hydraulics. The rear turbo was far too close to the clutch master cylinder outlet, which meant it was impossible to hook up the clutch line. I had to find another master cylinder with the outlet in a different location, and after a bit of searching I found a Ford Cortina unit which has the same bore diameter and an outlet on top of the cylinder instead of on the side. The bolt pattern is vertical as opposed to diagonal on the Supra master cylinder, so a bit of creative engineering was required to make it fit. Incredibly, it turns out this steel flange which originally sat between the crankshaft and the torque converter is the perfect adapter for the job - the bolt pattern was exactly the same as the master cylinder bolt spacing! All I had to do was lengthen the pushrod so it would reach the clutch pedal, and I had a functioning clutch. Sweet!
