Z31 Transmission Specifications and Variations

Manual Transmission Specifications

• Non-turbo (All Years): FS5W71C (Nissan 5-speed, highly reliable)
• Turbo 1984-1986: FS5R90A (Borg-Warner T-5 5-speed)
• Turbo 1987-1989: FS5R30A (Nissan 5-speed, shared with Z32 turbos, trucks, Pathfinders, etc.)
  • 1987 model has a unique gear set
  • 1988–1989 models use a different ratio

All Z31 manual transmissions have synchros on every forward gear. Change your gear oil regularly, and these boxes will last for years without trouble!

Automatic Specifications

The Z31 was offered with 4 different Jatco automatic transmissions. All are the 4N71B model. 1985-1989 models feature an electronic lockup function and these car called the E4N71B. The main difference between all these models are with the number of clutches depending on the use with Turbo models having more clutches in them for higher power holding.

These transmissions are based on the light-duty L4N71B model previously used in the Datsun 810. The E4N71B allows lockup in all forward gears, using a microprocessor to electronically control the torque converter lockup.

The overdrive switch in these automatics includes a temperature sensor, preventing the transmission from shifting into overdrive until the fluid is sufficiently warmed up. This helps to avoid possible damage from cold shifts.

Level 10 used to make an upgrade kit for these transmissions that could handle 500+ hp, but it is no longer available.

Interchange

All Z31 transmissions are completely interchangeable. They have no problems bolting up to the motor. One problem is they don't always mount to the body correctly. You may have to drill and tap new holes for the transmission mount.

Transmission Mount Bolt Holes (1986 Non Turbo Automatic Model Shown with a FS5W71C Installed)

Pro Tip: Driveshaft Sizing

Each transmission has its own output shaft size and overall length. If you have a two-seater Z31, just match your new transmission with a driveshaft from another two-seater with the same transmission. Four-seater owners, especially those converting to turbo or manual, may need to have a driveshaft lengthened—these are much harder to find. Plenty of FS5W71C 2+2 driveshafts exist, so that's your easiest route for 2+2 5-speed swaps.

Pro Tip: Z32 Manual Transmissions

Want to run a Z32 manual transmission in your Z31? You'll need an '89–'91 Maxima SE flywheel, and you'll have to modify both the stock shifter and transmission mount. Read more about this swap here.

Pro Tip: Automatic Swaps & Flexplates

If you're swapping one automatic for another, make sure you're matching the same transmission type—Non-Turbo for Non-Turbo, Electronic for Electronic, etc. If the torque converter doesn't line up properly with the flexplate (either too tight or too far away), you likely have mismatched parts. Turbo and Non-Turbo automatics use different torque converters and flexplates. Always match the converter and flexplate to your transmission to avoid pump drive damage!