Changing the transmission filter should be considered at each change of fluid. The benefits of a transmission fluid change can be enhanced by a few extra steps. Check with a mechanic before changing the transmission filter.
Changing transmission fluid includes cleaning and draining the sump. New fluid is then added to the transmission to replace the drained fluid. The capacity of fluid in the Ford E40D transmission is approximately 16.5 qts. The fluid should be changed every 30,000 miles. In heavy duty operation, annual changes are recommended.
Filter Change and Pan Capacity
Changing the transmission filter is recommended if sludge and debris are noticed at the time of a fluid change. A filter change will not affect fluid capacity. The E40D pan will hold 3.0 qts. over stock in two-wheel drive vehicles and 3.5 qts. over stock in four-wheel drive vehicles. Each transmission has a stock requirement for fluid inside the transmission. This is not included in pan capacity.
Although the filter change will not affect the fluid capacity of the pan, other changes will affect the overall capacity needed in a fluid change. When changing the transmission fluid and filter, consideration should be given to draining the torque converter and cooler at this time. Fluid from the main reservoir is drained during a fluid change. Old fluid remains in the torque converter and cooler. If not changed, this old fluid will mix with the fresh fluid of a conventional fluid change. If fluid in the torque converter is drained as well, the capacity will increase from 16.5 to 25 qts.