G 20 3/4 Ton Van V8-305 5.0L VIN H 4-bbl (1984)
Accumulator: Customer Interest
A/T - No Engine Braking In Drive 2 (D2)
Number:
88-378-7A
Section:
7A
Date:
DEC., 1988
Subject:
NO ENGINE BRAKING IN DRIVE 2 (D2)
Model and Year:
1978-88 TRUCKS WITH THM 400/475
FIGURE 1 - THM 400/475, HYDRA-MATIC 3L80/3L80-HD TRANSMISSION IDENTIFICATION INFORMATION
FIGURE 2 - VALVE BODY
TO:
ALL CHEVROLET DEALERS
This bulletin covers no engine braking in Drive 2 (D2) selector range caused by a broken plastic Front Accumulator Piston (303). The transmissions
affected are the THM 400/475/ HYDRA-MATIC 3L80/3L80-HD Transmission. The die cast aluminum piston can be used in service for this condition
and will reduce the chance of any broken or cracked pistons.
DATE OF PRODUCTION CHANGE:
(Figure 1)
August 1, 1988 (Julian Date 214) all 1989 THM 400/475/ HYDRA-MATIC 3L80/3L80-HD Transmissions were built with the aluminum Front
Accumulator Piston (303).
SERVICE PARTS INFORMATION:
(Figure 2)