Drivetrain - Electric Shift Transfer Case Shift Problems

Group Ref.: Transmission

Bulletin No.: 367401

Date: March, 1994

SUBJECT:
ELECTRIC SHIFT TRANSFER CASE (NP233E) DOES NOT SHIFT OUT OF 4-LOW, GRINDS WHEN SHIFTING FROM 4-LOW TO 4-HIGH, OR SLIPS OUT OF 4-HIGH (REVISED RANGE SHIFT FORK, HUB KIT, AND SHIFT SECTOR RELEASED)

MODELS:
1992-93 CHEVROLET AND GMC TRUCK T TRUCKS
EQUIPPED WITH ELECTRIC SHIFT TRANSFER CASE (RPO NP1)





CONDITION:

Some owners may experience the following conditions:

1. Grinds when shifting from 4-Low to 4-High.

2. Will not shift out of 4-Low.

3. Slips out of 4-high (usually results In ratchet noise).

CAUSE:

These conditions may be due to the range shift fork and range shift hub preventing proper shift engagement of the planetary carrier and the input gear.

CORRECTION:

A revised range shift fork assembly (including pads), input gear, and range shift hub service kit (Transfer Case Field Service Kit, P/N 15971058) to correct these conditions are now available. The parts have been revised to allow for proper shift engagement. In addition, a revised shift sector (P/N 12544302) should be installed in conjunction with the Transfer Case Field Service Kit.

SERVICE PROCEDURE:

Please refer to Section 7D TRANSFER CASE in the appropriate LIGHT DUTY TRUCK UNIT REPAIR MANUAL (Disassembly and Assembly of Internal Components).


SERVICE PARTS INFORMATION:





Parts are expected to be available from GMSPO on 3/7/94.

WARRANTY INFORMATION:





For vehicles repaired under warranty use: