DRIVETRAIN
MANUALTRANSMISSION
REMOVAL & INSTALLATION
Fig. 1: Use guide pins when removing and installing the transmissionFig. 2: Exploded view of the transmission mounting— 85mm 5-speed shown, others similar
1. Place the transmission in third or fourth gear.
2. Jack up your vehicle and support it with jackstands.
3. Drain the transmission.
4. Unplug the speedometer cable or Vehicle Speed Sensor (VSS) connector, back-up lamp wire and any other wires that would interfere with transmission removal.
5. Remove the gearshift lever. Plug the opening to keep out dirt.
6. Remove driveshaft after making the position of the shaft to the flange.
7. On 4WD models, remove the transfer case.
8. If necessary, remove the parking brake and controls.
9. Remove the exhaust pipes.
10. If equipped, remove the clutch slave cylinder and position it aside.
11. Position a transmission jack or its equivalent under the transmission to support it.
12. Remove the crossmember. Visually inspect to see if other equipment, brackets or lines must be removed to permit removal of transmission.
NOTE: Mark position of crossmember when removing to prevent incorrect installation. The tapered surface should face the rear.
13. Remove the flywheel housing underpan.
14. On NVG 4500 models, unbolt the transmission-to-bell housing bolts.
15. On all except the NVG 4500 models, remove the top two transmission-to-housing bolts and insert two guide pins.
NOTE: The use of guide pins will not only support the transmission but will prevent damage to the clutch disc. Guide pins can be made by taking two bolts, the same as those just removed only longer, and cutting off the heads. Cut a slot in the head that will receive a screwdriver. Be sure to support the clutch release bearing and support assembly during removal of the transmission. This will prevent the release bearing from falling out of the flywheel housing.
16. On all except the NVG 4500 models, remove the remaining bolts and slide transmission straight back from engine. Use care to keep the transmission drive gear straight in line with clutch disc hub.
17. Remove the transmission from beneath your vehicle.
To install:
Installation is the reverse of removal but please note the following important steps.
18. Make sure the transmission is in third or fourth gear. On NVG transmissions, place the transmission in Neutral.
19. Coat the input shaft splines with high temperature grease.
20. On all except the NVG 4500 models, install the guide pins in the top 2 bolt holes.
21. On NVG 4500 models, install the transmission-to-housing bolts.
WARNING
Do not force the transmission into the clutch disc hub. Do not let the transmission hang unsupported in the splined portion of the clutch disc.
22. On all except the NVG 4500 models, tighten the transmission-to-engine bolts to 35 ft. lbs. (47 Nm). On NVG 4500 models tighten transmission-to-housing bolts to 74 ft. lbs. (100 Nm).
Driven Disc and Pressure Plate
REMOVAL & INSTALLATION
CAUTION
The clutch driven disc may contain asbestos, which has been determined to be a cancer causing agent. Never clean clutch surfaces with compressed air! Avoid inhaling any dust from any clutch surface! When cleaning clutch surfaces, use a commercially available brake cleaning fluid.
NOTE: Before removing the bellhousing, the engine must be supported. This can be done by placing a hydraulic jack, with a board on top, under the oil pan.
1. Remove the slave cylinder.
2. Remove the transmission.
3. If equipped, remove the inspection cover from the clutch.
4. On all NVG 4500 models, remove the bellhousing.
5. Remove the throwout spring and fork.
6. Remove the ballstud from the bellhousing.
7. Install a pilot tool (an old input shaft makes a good pilot tool) to hold the clutch while you are removing it.
NOTE: Before removing the clutch from the flywheel, mark the flywheel, clutch cover and one pressure plate lug, so that these parts may be assembled in their same relative positions. They were balanced as an assembly.
8. Loosen the clutch attaching bolts one turn at a time to prevent distortion of the clutch cover until the tension is released.
9. Remove the clutch pilot tool and the clutch from the vehicle.
10. Check the pressure plate and flywheel for signs of wear, scoring, overheating, etc. If the clutch plate, flywheel, or pressure plate is oil-soaked, inspect the engine rear main seal and the transmission input shaft seal, and correct leakage as required. Replace any damaged parts.
Fig. 2: Remove the clutch and pressure plate bolts11.
Fig. 3: Remove the clutch and pressure plate assembly . . .12.
Fig. 4: . . . then separate the clutch and pressure plate13.
Fig. 5: Be sure that the flywheel surface is clean, before installing the clutch14. To install:
15. On vehicles equipped with a gasoline engine, lubricate the pilot bearing with a few drops of machine oil. On vehicles equipped with diesel engines, the bearing is sealed and does not require lubrication.
16. Install a new pilot bearing. A brass drift or equivalent may be used to drive the bearing into place on vehicles equipped with a gasoline engine. On vehicles equipped with diesel engines, use a suitable pilot bearing driver.
17. Install the pressure plate in the cover assembly, aligning the notch in the pressure plate with the notch in the cover flange. Install pressure plate retracting springs, lockwashers and drive strap-to-pressure plate bolts. Tighten to 11 ft. lbs. (15 Nm). The clutch is now ready to be installed.
NOTE: The manufacturer recommends that new pressure plate bolts and washers be used.
18. Turn the flywheel until the X mark is at the bottom.
19. Install the clutch disc, pressure plate and cover, using an old input shaft as an aligning tool.
20. Turn the clutch until the X mark or painted white letter on the clutch cover aligns with the X mark on the flywheel.
21. Install the attaching bolts and tighten them a little at a time in a crossing pattern until the spring pressure is taken up. On 1988–94 models, tighten the bolts to 22 ft. lbs. (30 Nm) on 4.3L, 5.0L and 5.7L engines; 32 ft. lbs. (43 Nm) on 6.2L and 6.5L engines; and 24 ft. lbs. (33 Nm) on 7.4L engines. On 1995–98 gasoline models tighten the bolts to 30 ft. lbs. (41 Nm). On 1995–98 diesel models, tighten the bolts to 25 ft. lbs. (34 Nm).
22. Remove the alignment tool.
23. Coat the rounded end of the ballstud with high temperature wheel bearing grease.
24. Install the ballstud in the bellhousing. Pack the ballstud from the lubrication fitting. Coat the rounded end of the ballstud with grease.
25. Pack the inside recess and the outside groove of the release bearing with high temperature wheel bearing grease and install the release bearing and fork.
26. Install the release bearing seat and spring.
27. Install the clutch housing. Tighten the bolts to:
o 1988–90 R/V Series: 40 ft. lbs. (54 Nm)
o 1988–90 C/K Series: 55 ft. lbs. (75 Nm)
o 1991 Models: 31 ft. lbs. (43 Nm)
o 1992–94 Models: 29 ft. lbs. (39 Nm)
o 1995–98 Models: 23 ft. lbs. (31 Nm)
28. Install the transmission.
29. Install the inspection cover.
30. Install the slave cylinder. Tighten the bolt to 13 ft. lbs. (18 Nm).
31. Bleed the hydraulic system.
Fig. 6: Install a clutch alignment arbor, to align the clutch assembly during installation32.
Fig. 7: Apply a thread locking agent to clutch assembly bolts33.
Fig. 8: Be sure to use a torque wrench to tighten the bolts34.
Fig. 9: Grease the clutch release fork ballAUTOMATICTRANSMISSION
REMOVAL & INSTALLATION
NOTE: It would be best to drain the transmission before starting.
1. Disconnect the battery ground cable.
2. Remove the air cleaner.
3. If equipped, disconnect the detent or TV cable at the throttle lever.
4. On 4WD models, remove the transfer case shift lever knob and boot.
5. Raise and support the truck on jackstands.
6. Disconnect the shift linkage from the transmission.
7. If it is necessary to disconnect the fuel line, relieve the fuel system pressure. Disconnect the fuel lines.
8. Remove any skid plates that would interfere with transmission removal.
9. Drain the transmission fluid.
10. Remove the driveshaft(s), after matchmarking its/their flanges.
11. Detach the speedometer cable or Vehicle Speed sensor (VSS) connector, downshift cable, vacuum modulator line, shift linkage, throttle linkage, electrical wiring, the fluid cooler lines, or any other component that would interfere with transmission removal.
12. Remove the dipstick tube.
13. If necessary, remove the starter motor.
14. If necessary, disconnect the support bracket at the catalytic converter.
15. Support the transmission on a transmission jack and unbolt the transmission rear mount or the transfer case adapter from the crossmember.
16. Remove the crossmember.
17. Remove any transmission support braces. Note their exact positions for installation.
18. Remove the torque converter underpan, matchmark the flywheel and converter, and remove the converter bolts.
19. If necessary for clearance, move the exhaust system aside.
20. If necessary for clearance, disconnect the parking brake cable.
21. Remove the transfer case and the adapter.
22. Support the engine on a jack and lower the transmission slightly for access to the upper transmission-to-engine bolts.
23. Remove the transmission-to-engine bolts and pull the transmission back. Rig up a strap or keep the front of the transmission up so the converter doesn't fall out.
To install:
Installation is the reverse of removal but please note the following important steps.
24. Tighten the transmission-to-engine bolts to 35 ft. lbs. (47 Nm).
NOTE: Make sure that the torque converter-to-flexplate matchmarks are aligned, the torque converter is flush with the flywheel and the converter turns freely by hand.
25. On all except 1996–98 models, tighten the converter bolts to 50 ft. lbs. (68 Nm).
26. On 1996–98 models, tighten the converter bolts to 46 ft. lbs. (63 Nm).
27. Tighten the transmission support brace bolts to 35 ft. lbs. (47 Nm).
28. On all except 1991–98 models, tighten the crossmember retainers to 35 ft. lbs. (47 Nm).
29. On 1991–98 models tighten the crossmember retainers to 56 ft. lbs. (77 Nm).
30. On 1988–94 4WD models, tighten the transfer case-to-transmission attaching bolts to 24 ft. lbs. (32 Nm) and the transfer case-to-frame bracket bolts to 35 ft. lbs. (47 Nm).
31. On 1995–98 4WD models, tighten the adapter-to-transfer case and adapter-to-transmission bolts to 33 ft. lbs. (45 Nm).
Fig. 1: Automatic transmission and related components— THM400, 4L60E and 4L80E32.
Fig. 2: Automatic transmission and related components— THM700R4ADJUSTMENTS
Shift Linkage
1. Raise and support the front end on jackstands. Block the rear wheels.
Fig. 1: Shift linkage— THM 400 and THM 700R4 transmissions2.
Fig. 2: Shift positions— THM 400 and THM 700R4 transmissions3.
Fig. 3: Shift linkage— 4L60E and 4L80E transmissions4.
Fig. 4: Shift positions— 4L60E and 4L80E transmissions5. Loosen the shift lever bolt or nut at the transmission lever so that the lever is free to move on the rod.
6. Set the column shift lever to the neutral gate notch, by rotating it until the shift lever drops into the Neutral gate. Do not use the indicator pointer as a reference to position the shift lever, as this will not be accurate.
7. Set the transmission lever in the neutral position by moving it clockwise to the park detent, then counterclockwise 2 detents to neutral.
8. Hold the rod tightly in the swivel and tighten the nut or bolt to 17 ft. lbs. (23 Nm) on all but the 4L80E transmission. On the 4L80E transmission, tighten the bolt to 20 ft. lbs. (30 Nm).
9. Lower the vehicle.
10. Move the column shifter to park and check that the engine starts. Check the adjustment by moving the selector to each gear position.
Shift Cable
NOTE: This procedure applies to 4L60-E and 4L80-E transmissions.
1. Place the transmission in park and apply the parking brake.
2. Raise and support the vehicle on jackstands.
3. On the shift cable end slide the black retaining clip forward just enough to allow the white lock button to be out.
NOTE: Do not push the white lock button completely out.
4. Push the white lock button out just far enough to free the metal core adjust body inside the core.
5. Inspect the core adjust body for dirt or debris that may restrict its travel.
6. If there are any restrictions found the shift cable end should be washed with soap and water. If after cleaning the cable the travel of the core adjust body is still restricted the shift cable assembly must be replaced.
7. Lower the vehicle, turn the ignition switch ON and move the transmission lever from park to one-to-ten times.
8. Place the shift lever in park and turn the ignition switch OFF. Raise and support the vehicle on jackstands.
9. Make sure the transmission is in mechanical park by rotating the control lever clockwise until it stops.
10. Push the white lock button in to secure the core adjuster body adjuster and slide the black retainer clip rearward until it covers the white lock button and locks in place over the shift cable end.
11. Lower the vehicle and turn the ignition switch ON.
12. Move the shifter through the gear ranges and ensure that the light comes on under the shift column letter when the shifter is positioned under that letter.
13. Ensure that the engine starts only when the transmission is placed in park or neutral. Adjust the park/neutral switch if necessary. Refer to the park/neutral switch adjustment procedure in this section.
14. Turn the ignition switch to the LOCK position and ensure that the key can be removed in the park position only.
15. Release the parking brake, start the engine and check for proper transmission shift operation.
Throttle Valve Cable
NOTE: This procedure applies to the THM 700R4 transmission.