A/T - Oil Cooler Flushing/Flow Check: Overview
File In Section: 7 - TransmissionBulletin No.: 77-71-59
Date: June, 1997
INFORMATION
Subject:
Automatic Transmission Oil Cooler Flushing and Flow Check Procedures
Models:
1997 and Prior GM Vehicles with Automatic Transmissions
Including:
Jaguar Cars Limited
Rolls-Royce Motor Car
Aston Martin Lagonda Limited
Reumech Ermetek
AM General
Isuzu
GM Brazil
GM Venezuela
GM Holden
Daewoo Motor Company
GM studies indicate that plugged or restricted transmission oil coolers and pipes cause insufficient transmission lubrication and elevated operating temperatures which can lead to premature transmission wearout. Many cases could have been prevented by following published procedures for transmission oil cooler flushing and flow checking. This procedure includes flushing and flow checking the auxiliary transmission oil cooler, if equipped.
GM requires that transmission oil cooler flushing and flow checking be performed whenever a transmission is removed from the vehicle for service within warranty, including:
- Goodwrench SRTA installation
- major overhaul
- torque converter replacement
- oil pump replacement
Only GM Goodwrench DEXRON(R)-III automatic transmission fluid should be used when doing warranty repair on GM transmissions.
Time allowance for performing the cooler flushing and flow checking procedure has been included in the appropriate labor time guide operations since the 1987 model year. The service procedure steps for oil cooler flushing are as follows: