Z31 Automatic to Manual Transmission Swap

Take out the center console

See fiche section 7E12: or Section 11 Sub Section 21 of the Haynes manual.

There are a couple of bolts behind the "300ZX" plate on the center console and a few more in the console box.

Take out the A/T shifter

See fiche section 4J08:

Remove the 2 screws on the back of the shifter


Now remove the 3 screws holding the cover to the shifter plate

Disconnect the two harnesses that are sometimes deep into the driver side Transmission well carpet.

You'll also need to disconnect the shift link mechanism from under the car. I did this later when I jacked up the car.

Install the brake pedal

I started with the most difficult step - replacing the brake pedal (see fiche Section 4L05).

1. Disassemble your A/T brake pedal only from it's mounting by removing Brake Booster rod and the piviot Pin from the assembly
2. Disassemble the 5-spd pedal from its plate (keep spring/shaft)
3. Start putting the pedal in. A royal PITA to align the pedal shaft while trying to maintain the spring in position in order to bolt her in place -you'll see what I mean when you get there. PATIENCE, A LOT OF IT, and it'll eventually get in. I used a rope to pull the spring compressed, then with a guide pin at the other end of the bore for the brake pedal shaft (item #46582), I was able to get it in. Torque tightening bolt to 22-30ft-lb

Install the clutch pedal assembly

The clutch pedal assembly includes the pedal itself, its mounting bracket and the clutch master cylinder.

1. If using the old master cylinder, make sure to clean it thoroughly.
2. Take out the windshield washer fluid reservoir and on the firewall you'll see a plate bolted where the clutch pedal shaft will go through.
   
   
   
3. Take that plate out
4. Install the clutch pedal and master cylinder
5. Torques: Clutch master cylinder securing plate: 5.8-8.7ft-lb; Clutch pedal push rod: 5.8-8.0ft-lb; Clutch pedal lock nut:12-16ft-lb.
6. Don't install the clutch hydraulic line at this point as there is not enough room yet.

Automatic Transmission Removal

Geting the Car Preped

Raise the car up as high and as safely as possible and USE JACK STANDS to support the car. You have to raise it high otherwise the Transmission dip stick tube will not clear frame when time comes to remove transmission.

NOTICE! Never work under car without properly securing jack stands under the vehicle.

Replacing Rear Oil Seal, Flywheel, and Clutch Assembly

Once the A/T is removed, you'll see a flex plate and a steel ring where the converter sat. Removing this ring is the next challenge (second only to the brake pedal). Options:

• Use a puller (AutoZone or Harbor Freight rent them)
• Use a wrench to pop it loose
• Socket + grease pressure method
• A blind side puller also works well

1. Remove the small circular drive plate and flex plate.
2. Replace the rear oil seal on the engine. This is likely your only opportunity—don’t skip it.
3. Install the clutch hydraulic tube, slave cylinder, and damper. Use a flare nut wrench and follow torque specs precisely.
4. Torque Specs:
   • Damper bolts: 5.8–8.0 ft-lb
   • Slave cylinder bolts: 22–30 ft-lb
5. Press the brass pilot bushing gently into place. Leave clearance to allow future removal; don’t bottom it out.
6. Insert the dust plates:
   • Small one first (toward engine)
   • Full one next
   • Align with dowel pins; can be reinserted later if needed
7. Install the resurfaced 5-speed flywheel. Bolt the Flywheel to the crankshaft using blue Lock-tight on the bolts (Torque: 72–80 ft-lb).
8. Bolt the clutch plate assembly in this order:
   • Clutch pressure plate (next to flywheel)
   • Clutch disk
   • Use a clutch alignment tool for accuracy
   • Torque the flywheel bolts: 16–22 ft-lb again with blue Lock-tight on them

Installing 5-Speed Transmission

You've cleaned and prepped the 5-speed transmission. Place it on the transmission jack and slide it under the car. Follow these steps carefully:

1. Align the transmission input shaft to the driveshaft. It may connect easily or take hours. Be patient and do not force it.
2. Once aligned, bolt the transmission to the engine.
   • Bolts below the starter: 22–29 ft-lb
   • Top bolts: 29–30 ft-lb
   • Don't forget to reinstall dust plates and follow earlier alignment tips
3. While the jacks are still supporting the engine and transmission, install the crossmember and transmission bushing. Torque: 33–44 ft-lb (based on engine mount specs)
4. Reconnect the oil temperature sensor harness.
5. Reinstall the starter and reconnect the negative battery terminal.
6. Reinstall the driveshaft using correct torque specifications.
7. Reinstall the exhaust components. Note: If using a turbo front tube, modify heat shield with a wooden mallet to clear the mount.
8. Install the original speedometer pinion with a new O-ring.
9. Torque the 5-speed driveshaft to 29–33 ft-lb.
10. Final exhaust torque specs:
    • Front tube to engine: 34–45 ft-lb
    • Front tube to catalytic converter: 23–32 ft-lb
    • Cat to mid tube: 31–42 ft-lb
11. Adjust the emergency brake. Torque: 2.3–3.2 ft-lb. Aim for 8–10 notches before full engagement.

Fill Her Up With Oil

There are several ways to fill the transmission with oil. One common method is threading a plastic tube from the engine bay to the transmission oil inlet, then pouring in: 5-1/8 qt of Redline MT-90 synthetic (or 4-1/4 qt for N/A). You'll know it's full when oil starts to drip out of the fill port.

1. Fill the clutch master cylinder with DOT-3 brake fluid and bleed the system. Start with the damper, then the slave cylinder. A friend helps a lot here!
2. Adjust free play in the brake and clutch pedals as precisely as possible.