K 2500 Suburban 4WD V8-5.7L VIN R (1999)
Transfer Case Actuator: Technical Service Bulletins
Transfer Case - Four Wheel Drive Inoperative
File In Section: 04 - Driveline Axle
Bulletin No.: 99-04-21-002
Date: April, 1999
TECHNICAL
Subject:
Four-Wheel Drive (4WD) Inoperative
(Replace Transfer Case Actuator/Shift Detent Plunger)
Models:
1999 Cadillac Escalade
1998-99 Chevrolet and GMC C/K Models (Tahoe, Denali, and Yukon)
with 4L60-E or 4L80-E Automatic Transmissions (RPOs M30, MT1)
and NV246 Transfer Case (RPO NP8)
Condition
Some owners may comment that the 4WD is inoperative.
Cause
This condition may be caused by an inoperative transfer case motor (actuator).
Correction
A new transfer case Teflon(R)-coated shift detent plunger (poppet) has been developed in order to correct this condition. This coating on the exterior
surface of the poppet should reduce shift effort and wear. If you determine that the transfer case actuator is inoperative, replace the actuator and the
poppet. Use the following procedure and the part numbers listed below.
1.
Remove the transfer case actuator.
2.
Install a new transfer case actuator, P/N 12474401.
3.
Remove the transfer case oil drain plug. Drain the oil from the transfer case. Refer to the Transfer Case subsection in the appropriate Service
Manual. If the plug is difficult to remove or stripped, refer to Corporate Bulletin Number 99-04-21-001.
4.
Remove the plunger (poppet) screw. The poppet and the spring should come out with the screw.
Notice:
Do not overtighten the poppet screw.
Overtightening may damage the screw.
Important:
Verify that the 0-ring on the screw is not damaged. Replace a damaged 0-ring.
5.
Install the new coated poppet, P/N 12474072 (coated blue), the spring, and the screw.
Tighten
Tighten the screw to 14-20 N.m (10-15 lb ft).
6.
Install the transfer case oil drain plug.
Tighten
Tighten the drain plug to 16-24 N.m (12-18 lb ft).
Important:
Do not use standard DEXR0N(R)III. Performance of the transfer case may be impaired.
