Transfer Case - Shift Effort High or Blockouts: Overview
90chevy30Number: 90-328-7A
Section: 7A
Date: August 1990
Corp. Bulletin No.: 067407
Subject: HIGH TRANSFER CASE SHIFT EFFORT
Model and Year: 1988-90 K TRUCKS EQUIPPED WITH NEW PROCESS 241 TRANSFER CASE
TO: ALL CHEVROLET DEALERS
Some 1988-90 K-Trucks may experience high transfer case shift effort or blockouts when "shifting on the fly" from 2H to 4H under cold weather conditions (usually less than 32 degrees Fahrenheit). This condition may be corrected by the installation of the synthetic 75W90 gear lube described in Dealer Service Bulletin 89-223-7A. If the installation of this fluid does not result in a satisfactory shift effort, an "Easy Shift" package may be installed in the transfer case. This package was installed in production early in the 1990 model year and will provide reduced transfer case shift effort under cold weather conditions.
INVOLVED VEHICLES:
All 1988-90 K1, K2, K3 trucks equipped with New Process 241 transfer case and built prior to the VIN Breakpoints listed below:
Fort Wayne: LZI25644
Oshawa: L1111094
Pontiac East: LE115343