A/T - E40D Extension Housing Bushing Failure
TECHNICAL BULLETIN # 228TRANSMISSION: E4OD
SUBJECT: Extension housing bushing failure
APPLICATION: Ford
E4OD Extension housing bushing failure
The extension housing bushing in the back of an E4OD, (Figure 1) has been known to wear extensively, in a relatively short period of time, and cause rear seal leaks and driveshaft slip yoke wear problems.
This is usually caused by one of two different things. Either there is not enough lube oil getting to the bushing/yoke area, or else there are electrical grounding problems causing the driveshaft and transmission to be used as part of the electrical path back to battery ground.
Usually the lube oil problems can be corrected by making sure that enough lube oil is getting into the transmission, and that lube oil is being properly directed inside the unit.
Get the unit hot then check the cooler flow out of the return line. There must be at least one quart of oil out of the rear line in less than 20 seconds. If not there is a cooler restriction or converter charge problem.
There must be a good snug fit between the output shaft and the case bushings (Figure 2). As a rule of thumb there is an allowable .001"- .002" clearence per inch in bushing diameter.
If the unit is apart inspect this area closely. If your unit is still in the vehicle, remove the extension housing and make sure that the shaft doesn't move up and down much at all (approximately 1/16"). Shoot compressed air into the rear cooler line fitting after checking cooler flow. There should not be a lot of oil or air from behind the park gear.
While you're shooting air into the rear cooler fitting, you should notice a small stream of fluid/ air coming out of a tiny hole in the back of the case, Just below the park gear (Figure 3).
This hole is supposed to shoot oil along the housing right onto the yoke and bushing area. If everything else is okay, reattach the cooling line, get the fluid level right and start the engine. A solid stream of fluid should shoot out of the hole to the rear of the output shaft. If it doesn't get that far, try to gently ream the hole out with a # 66 wire (.033") drill, (Figure 4). Be careful not to change the angle of the hole.
Electrical grounding problems causing this bushing to fail can be quickly corrected by bolting on a ground strap from the transmission case to the crossmember, or from the engine block to the vehicle body.
Note
Be careful not to change the angle of the hole.