A/T - In Line Service Check Valve Usage

91ford15

Article No.
91-7-14

04/05/91


TRANSMISSION - E40D - IN-LINE SERVICE CHECK VALVE USAGE


LIGHT TRUCK: 1990-91 BRONCO, ECONOLINE, F SUPER DUTY, F-150-350 SERIES


ISSUE: In some cases both the in-line and case mounted check valves are mistakenly installed together to correct a delayed initial reverse engagement concern. Usage of the in-line check valve combined with the factory installed check valve fitting may actually restrict transmission lube flow and lead to potential failure.

ACTION: Do not use the in-line service check valve on any E40D transmission that is already equipped with a factory installed case mounted check valve. OASIS Message # 2155 and TSB 90-18-11 refer to a service only in-line check valve to correct delayed initial reverse engagement.


The factory installed case check valve can be identified by its gold color and 13/16 hex. It has been incorporated into the rear cooler line case fitting since 2/20/90, which includes some 1990 and all 1991 trucks.

If both valves are present, remove the in-line check valve and rejoin the cooler line sections or replace as required. Check all cooler lines and connections for leakage.

OTHER APPLICABLE ARTICLES: 90-18-11
WARRANTY STATUS: INFORMATION ONLY
OASIS CODES: 503000