How do you remove the transmission from an 1985 Nissan 720?

Answer 1

1970-86 (521, 620 and 720-D Series) F4W63, F4W71B and FS5W71B

1. Disconnect the negative battery cable.
2. On 1975-86 models only, remove the shift lever from inside the cab. It is retained to the shaft rail by a C-clip, accessible under the boot. Remove the C-clip and retaining pin, then remove the lever.
3. Raise the vehicle and support it with jackstands.
4. On 1970-74 models, unscrew the nut securing the bottom of the shifter to the transmission shifting mechanism.
5. Disconnect the exhaust pipe from the exhaust manifold. On trucks with a catalytic converter, also remove the exhaust pipe bracket next to the speedometer cable by unscrewing the two mounting bolts.
6. Remove the clutch slave cylinder from the transmission case.
7. Disconnect the speedometer cable from the transmission extension housing, then disengage the back-up light and transmission switch wires at the switch(es).
8. Remove the bracket holding the center bearing of the driveshaft on the third crossmember of the frame.
9. Remove the driveshaft(s).

   NOTE: On 4wd models, this requires removal of the transfer case, which should be performed at this time.

10. Support the engine with a floor jack located under the oil pan. Place a block of wood between the jack and the oil pan to prevent damage to the oil pan. Support the transmission with a jack.
11. Remove the rear engine mount securing bolts and the crossmember mounting bolts. The 1970-71 models (521 series) do not have a removable crossmember; only the rear engine/transmission extension housing mount is removable from the crossmember.
12. Remove the starter motor.
13. Remove the bolts securing the transmission to the engine, pull the transmission toward the rear until the transmission mainshaft is free of the back of the engine.
14. On 1970-71 models, place the rear of the transmission on the crossmember and then pull the transmission down toward the front of the truck and out from under the vehicle.
15. On 1972-86 models, separate the transmission from the engine, then lower the transmission out from under the truck.

    To install:

16. Before installing the transmission, clean the mating surfaces of the engine and transmission thoroughly.
17. Lightly coat the input shaft splines with grease.
18. Reverse the removal procedures. Tighten the engine-to-transmission bolts to 17-20 ft. lbs. (23-27 Nm) for 1970-73 vehicles, 29-36 ft. lbs. (39-49 Nm) for 1974-76 vehicles or to 32-43 ft. lbs. (43-58 Nm) for 1977-86 vehicles.

    NOTE: On the 5-speed transmission, the two bottom bolts are tightened to 7-9 ft. lbs. (9-12 Nm).

19. Tighten the crossmember-to-chassis bolts to 20-27 ft. lbs. (27-37 Nm) and the clutch slave cylinder mounting bolts to 18-22 ft. lbs. (24-30 Nm). Be sure to align the marks made earlier on the U-joint and differential flange when installing the driveshaft, to maintain driveline balance.