A/T - E40D ATF Leaking Out Vent
TECHNICAL BULLETIN # 274TRANSMISSION: E4OD
SUBJECT: ATF Leaking Out The Vent
APPLICATION: Ford E/F150-350, Bronco Series
DATE: Jan 1995
E4OD ATF Leaking Out The Vent
There are two primary reasons why ATF will leak out the vent.
1. The fluid level is too high.
2. The pump is warped, causing internal leaks.
The first reason is fairly straight forward. Make sure the fluid level is correct. Keep in mind that the dipstick may not be the proper one for the vehicle in question. The proper fluid level is approximately one-half inch below the pan rail.
The second problem can be the result of overheating. A pump that has been overheated can become warped causing EPC pressure to leak into the vent cavity. This can be prevented by making sure that the pump halves are flat. The pump body can be flat sanded. After flat-sanding the pump body, the end-clearance of the rotor should be .001"-.0015". The stator support will have to be machined. Before assembling the pump, apply a layer of thin sealant like Locktite(R) as shown in the figure. Flat washers should be used with the pump-to-stator support bolts to prevent them from bottoming out.