Converting a MkIV Supra Automatic to 6 Speed

Automatic Transmission Conversion to a 6 Speed

Can I swap from auto tranny to a six speed?

This is one of the most asked questions we receive at This question has its fruit in the fact that 6 Speed Twin Turbo Supra's are very rare and have a premium price. Many people find automatic Twin Turbo Supras or N/As are readily available and believe them to be more cost effective to purchase and then want to swap from the auto tranny or weak 5 speed to a 6 speed.

First. Yes, this is a swap that can be done and has been done.

How much does it cost and what is involved?

While pricing varies, here are some rough ideas and be sure to check out our parts list. Plan on spending $2500+ in conversion parts from Toyota (clutch pedal, flywheel, pressure plate, disk, clutch kit, clutch master cylinder, etc.) plus a new ( or used 6 speed tranny ($5000+) and approximately $1500 in labor. The change takes approximately a couple of days to a week to perform.

From there, your gearing will be off, as the differential ratios of the automatic and 6 speed cars are very different. At this point, you can either convert to a 6 speed's "220mm diff" or stick with the "200mm diff" that the automatics and 5 speed manual MkIVs came with. 6 speed differentials are much more rare and expensive, although they're also practically unbreakable up to and past 1000rwhp. The smaller differential has been shown to handle plenty of power (~800rwhp) with no issues with mechanical failure. To get the closest rear end (and thus, final drive ratio), the most cost effective solution is to use a GS400 diff, as the ring and pinion is interchangeable with the non-6 speed diffs. You will also need to have either a custom driveshaft or a 6 speed driveshaft, as the auto one will not offer enough spline contact area for much power at all.

Plan on spending a total of $10,000+ for this job, including installation. As you can see, it very quickly becomes more cost effective to sell your car and buy a 6 speed one instead.

Hope this helps. If you are still interested, we can get you every part required including clutch and brake pedals (the auto pedal is too wide for the clutch pedal to fit), master cylinder, slave cylinder, clutch hydraulic lines, clutch fork, clutch disc, pressure plate, flywheel, shifter, shifter tripod and assorted parts, interior trim piece, etc.