Transfer Case - Delayed, or No 4WD Engagement
Bulletin No.: 002/93Issued: 2/12/93
Revised
Category
R
Applicable Model/s
1991 Navajo
Subject:
AUTO-LOCKING HUBS
NOTE:
This bulletin supercedes Service Bulletin # 010/92, Cat. R. originally issued 5/6/92 and revised 7/10/92.
AFFECTED VINS
This bulletin applies to vehicles with a VIN of 4F2CU44X*MUM12260 or lower produced through March 30, 1991.
This bulletin does not apply to vehicles with a VIN equal to or greater than 4F2CU44X*MUM12661 and produced after March 30, 1991.
DESCRIPTION
Complaints regarding delayed 4WD engagement or no engagement are caused by damaged auto-locking hubs. Modifications have been made to the auto-locking hub and the transfer case assemblies since March 31, 1991. These changes were made to prevent hub damage and provide unrestricted engagement.
Damage occurs when the auto-locking hub assembly and the transfer case electromagnetic clutch disengages prior to lock-up. Symptoms of this damage are ratcheting or clicking noises when engagement is attempted.
Design modifications have been made on production vehicles since March 31, 1991. These modifications were made to increase transfer case clutch efficiency, reduce engagement effort in the hub assembly and change axle lubricant to reduce resistance.
Vehicles produced prior to March 31, 1991 that experience delayed or no engagement should have hub assemblies inspected for noise and damage.
If the hubs are damaged, proceed to the repair procedures listed in this bulletin. If no damage is evident, refer to the Troubleshooting Section of the applicable Workshop Manual for further assistance.
REPAIR PROCEDURE
1. Determine if the vehicle VIN number is below 4F2CU44X*MUM12661.
2. Remove the left and right front automatic locking hubs and camming assemblies and replace with new assemblies (ZZL0 33 2XY). Refer to Section R of the Workshop Manual.
3. Inspect the wheel bearing retaining nut for damage and presence of foreign material which would diminish wheel bearing life.
4. Replace the wheel bearing retaining nut if damaged (see Workshop Manual Section R). The nut comes with the hub assembly.
5. Remove the following old parts and replace them with corresponding new parts. Refer to the Workshop Manual Section J for service details.
^ Clutch Coil Assembly (ZZL1 17 736)
^ Clutch Housing (ZZL0 17 736A)
^ Lock-Up Collar (ZZL1 17 929B)
^ Lock-Up Fork (ZZL0 17 912)
^ Return Spring (ZZL1 17 477A)
^ Sleeve Spring (ZZL1 21 246)
6. Install the sleeve spring (ZZL1 21 246) into the bore of the lock-up collar, large end first.
7. Determine if the vehicle VIN number is below 4F2CU44X*MUM08415. If it is below, replace the front axle lubricant with new lubricant (ZZL0 26 001).
A. Extract the old lubricant using a suction gun.
NOTE:
Breaking the carrier seal is not a recommended method of extracting the lubricant.
B. Refill the front axle housing with 56 ounces of new lubricant (ZZL0 26 001) using a suction gun.
NOTE:
One (1) container of lubricant (ZZL0 26 001) equals 32 ounces. 56 ounces are required to fill the axle housing.
PARTS INFORMATION
WARRANTY INFORMATION
Warranty Type Code: A
Customer Comment Code: 92
Damage Code: 9A
Part No. of Main Cause: ZZL0 33 2XY
Related Part No.: See Parts Information chart above.
Operation No./Labor Hour: M0501BRX/0.9 Hrs. (Hub Replacement)
A/T - K0102XHX / 5.1 Hrs. (Transfer Case Overhaul);
M/T - J0102XHX / 5.1 Hrs. (Transfer Case Overhaul);
YY0045RX / 0.2 Hrs. (Front Axle Lubricant Drain and Refill)