The transfer case is actuated by an electrically controlled vacuum servo system. When the all wheel drive switch is placed in the ON position, a relay activates the 4WD solenoid valve. The 4WD solenoid valves allows vacuum to be created in the left hand chamber of the vacuum servo. The vacuum moves the servo rod and sliding collar into engagement with the transfer case output gears, driveshaft and rear axle. When the 2WD switch is turned ON a relay activates the 2WD solenoid valve. Vacuum is created in the right hand chamber of the vacuum servo disengaging the transfer case, driveshaft and rear axle output gears. The transfer case lubrication is integral with the transaxle. The transaxle/transfer case assembly requires 8.3 quarts of Mercon automatic transmission fluid.
REMOVAL & INSTALLATION
See Figures 1 and 2
- Disconnect the negative battery cable.
- Raise and safely support the vehicle.
- Using a light hammer and a dull chisel, remove the cup plug from the transfer case and drain the oil.
- Remove the vacuum line retaining bracket bolt.
- Remove the driveshaft front retaining bolts and caps; disengage the front driveshaft from the drive yoke.
- If the transfer case is to be disassembled, check the backlash through the cup plug opening before removal in order to reset to existing backlash at installation. The backlash should be 0.012-0.024 in. (0.3-0.6mm) on a 3 in. (76mm) radius.
- Remove the vacuum motor shield bolts and the shield unit.
- Remove the vacuum lines from the vacuum servo.
- Remove the transfer case-to-transaxle bolts; note and record the length and locations of the bolts.
- Remove the the transfer case from the vehicle.
- Position the transfer case to the transaxle.
- Install the transfer case bolts in the proper positions and tighten the bolts, in sequence, to 23-38 ft. lbs. (31-38 Nm) for 197, 15-19 ft. lbs. (21-25 Nm) for 198-9 models, or 12-15 ft. lbs. (16-20 Nm) for 1110-11 models.
- Install the vacuum motor supply hose connector, vacuum motor shield and tighten the bolts to 7-12 ft. lbs. (9-16 Nm).
- Install the driveshaft-to-drive yoke, lubricate the bolts with Loctite® and tighten the bolts to 15-17 ft. lbs. (21-23 Nm). Install the vacuum line retaining bracket and tighten the bolt to 7-12 ft. lbs. (9-16 Nm).
- Refill the transaxle and lower the vehicle. Road test the vehicle and check the performance of the transfer case.
See Figures 3 through 14Disassembly
- Remove the negative battery cable.
- Raise the vehicle and support on jackstands.
- Drain the oil from the transfer case and remove the case from the vehicle.
- Remove the case side cover bolts.
- Clean the gasket material from the case and cover.
- Remove the housing retaining bolts and remove the gear housing assembly.
- Remove the O-ring and shims. Wire the shim stacks together for reassembly.
- Remove the snaprings from the vacuum servo shaft and shift fork. Be sure to wear eye protection when removing and installing the snaprings.
- Remove the shift motor assembly. Unfasten the shift fork and fork clips.
- Remove the transfer case bearing cap retaining bolts and cap.
- Rotate the bearing and remove the 2 piece snapring from the bearing.
- Using a thin prybar, remove the inner snapring which positions the input gear to the ball bearing. Slide the bearing toward the input gear and remove the outer snapring.
- Remove the cup plug. Slide the input gear toward the ball bearing until the input gear and bearing can be lifted out of the transfer case.
- Remove the ball bearing from the input gear.
- Remove the shift collar from the clutch shaft.
- Remove the pinion nut and washer from the clutch shaft. Use a breaker bar and holding tool T7P-7120-A or equivalent. Tap the clutch shaft from the transfer case, with a soft drift.
- Remove the pinion gear, outer bearing and shims from the transfer case. Be sure to wire the shims together for reassembly.
- Remove and discard the clutch shaft collapsible spacer.
- Mount the transfer case on holding fixture T57L-500-B or equivalent.
- Install the clutch shaft inner bearing cup removal too T7P-7120-D. Remove the inner and outer bearing, using a suitable slide hammer into the cup remover.
- Place the gear housing subassembly in a soft jawed vise. Remove the pinion nut, yoke end and washer.
- Tap on the drive gear with a soft faced hammer to remove from the gear housing.
- Remove and discard the collapsible spacer.
- Remove the inner bearing cone from the drive gear, using a suitable press and a pinion bearing cone remover.
- Mount the drive in a soft jawed vise. Remove the drive gear housing seal, using a roll head prybar or a suitable tool.
- Remove the inner and outer drive gear bearing cups, using a brass drift and a hammer. Be sure to remove any burrs and wipe the bores clean.
- Remove the gear housing from the vise. Install the new inner and outer drive bearing cups, using tool T7P-4616-A or equivalent.
- Clean the drive gear in a suitable solvent, clean and dry completely. Install a new inner bearing cone assembly using pinion bearing cone replacer T62F-4621-A or equivalent. Be sure to install a nut on the end of the drive gear to protect the shaft.
- Lubricate and install the new outer drive bearing cone. Install a new oil seal, using install tool T7P-7065-B or equivalent. Grease the end of the seal completely.
- Install a new collapsible spacer on the drive gear stem. Install the drive gear into the gear housing.
- Install the yoke end, washer and nut.
- Tighten the pinion nut in small amounts until the rotation effect is 15-32 inch.lbs. (1.7-3.5 Nm) with the new bearing. Do not exceed this specification or a new collapsible spacer will have to be installed.
- Remove the clutch shaft inner bearing using a press and a bearing puller tool D4L-1123-A or equivalent.
- Mount the clutch shaft in a soft jawed vise.
- Remove the clutch shaft needle bearings which center the input gears, using pilot bearing preplacer tool T7P-7120-C or equivalent, and a slide hammer.
- Install a new clutch shaft needle bearing, using a hammer and a pilot bearing replacer.
When installing the needle bearing into the clutch shaft, install;; it with the tapered end down, toward the clutch.
- Pack the bearing with grease to maintain prior needle position.
- Install the clutch shaft inner bearing cone, using a press and and bearing puller attachment D4L-1123-A or equivalent.
- Wipe bearing bores clean. Install the inner and outer bearing cups, using bearing cup replacer T7P-7120-B or equivalent.
- Install a new new collapsible spacer on the clutch shaft. Install the clutch shaft into the transfer case. Assemble the original shim and pinion gear.
- Assemble the washer and pinion nut. tighten the nut using a breaker bar and a holding wrench until the rotational effort is 4.0-8.0 inch lbs. (0.44-.10) with the new bearings. Do not exceed this specification or a new collapsible spacer will be required to obtain the proper preload.
- Position shims and a new O-ring onto the gear housing. Be sure to lubricate the O-rings.
- Install the gear housing subassembly to the transfer case and tighten the bolts to 8-12 ft. lbs. (11-16 Nm).
- Check the backlash between the drive and pinion gear. Correct backlash should be 0.004-0.006 inch. (0.10-0.15mm).
Check the gear contact tooth pattern. If a gross pattern error is detected with backlash correct, adjust the drive pinion gear shim stack. Increasing the shim stack should move the contact pattern on the drive (pull) side of the gear.
- Install the shift collar onto the clutch shaft.
- Slide the ball bearing onto the input gear. Install the input gear into the transfer case. Slide the small end of the input gear into the clutch shaft.
- Install the snapring onto the outer end of the shaft.
- Slide the bearing outboard and install the snapring onto the inner end of the input shaft. Make certain the snaprings are completely seated in the grooves.
- Install the 2 piece snapring into the groove for the ball bearing in the transfer case.
- Install the bearing cap and retainer bolts. Tighten the bolts to 18-24 ft. lbs. (24-33 Nm).
- Inspect the shift fork clips and replace as necessary. Install the shift fork onto the clutch collar.
- Install a new O-ring onto the vacuum servo shaft. Lubricate O-ring with automatic transaxle fluid.
- Install the vacuum servo assembly into the transfer case. Install the snapring, making certain it is fully seated in the groove.
- Install the shift fork snaprings.
- Apply a bead of silicone rubber sealer on the cover surface. Install the transfer case side cover and tighten the bolts to 7-12 ft. lbs. (9-16 Nm).
- After checking the backlash, install the transfer case onto the transaxle.
- Check all hardware for tightness. Start vehicle, and check for fluid leaks.