E40D Transmissions:
Complaints and Cures
Ford has been using the C6 automatic transmission since 1966 in almost all of their trucks, and some of their cars, with a tremendous amount of success, so it's no wonder that when the engineers were faced with having to come up with a more fuel efficient 4-speed automatic transmission for their truck line, they chose to "update" the proven C6 design. But with changes usually follows problems . . . . and the E40D is no exception. The E40D first hit the streets in 1989, and immediately underwent changes in 1990; A different checkball lineup in the case channel area. From the very first one that entered our shop (and reentered . . . . .and reentered . . .ETC.), we knew that these transmissions had some "built-in problems." We made numerous calls to ATSG* and learned a great deal. Since then, I have done a great deal of them, but, for a while, with limited success. Now I'm quite happy with the way these rebuilt units are working for me. I hope you find these tips helpful. Please E-mail me at celery@pinsight.com if you hear of any more fixes on this or any other transmission, or if you have a suggestion for another topic for a future article.
E40D Complaints and Fixes
- Worn center support where forward clutch rings ride. Causing the forward clutch to burn up prematurely.
- There is an updated center support from Ford (Part#F4TZ-7A-130B) with a bearing that supports the forward clutch housing and overdrive-ringgear support much better. Omega Machine also makes an updated support with a bushing to center the whole mess. Also, I ALWAYS replace ALL the bushings in the unit. Every one of these units has worn-out case and sungear bushings.
- Poor second gear shift quality and/or burnt intermediate clutches.
- Many of the gas powered trucks have only 2 intermediate clutches. . .replace them with 3 Borg-Warner brand clutches and a thinner pressure plate(from a diesel or a 460). Also, I like the Gil-Younger shift kit (Transtar part#K73908); It seems to make the shifts more "crisp", and furnishes better "Lock-up" characteristics.
- Poor quality shifts, and Lock-up TOO early, and over-all "Wish it was a C6" feeling felt by the owner who just shelled out $30,000 for a new truck and now I want $2000+ to fix. "Ouch!"
- By far the greatest thing that I have found to make the customer a little happier when he makes his mortgage payment on his transmission repair, is a "New-and-Improved" Solenoid body from Autotrans Group . You can get these buggers through RPM and I think TransStar. (RPM part#E36949). This thing is trick! It raises lockup engagement speed, crisps up shifts and basically puts a smile on all the technician's faces during a test drive, and, perhaps best of all, it's cheaper than the new Ford solenoid bodies that we were buying before! (Do you think Autotrans Group will hire me as a rep?)
During Overhaul
Make sure during overhaul that you check both sprags and the roller clutch and races Carefully. If any flat spots are seen on the sprag "dog-bones" replace the sprag. I replace both sprags and the low spring-and-roller assembly every time, and the rear race in the case 90% of the time. Also, make sure not to over-torque the center support bolts. I use blue Loctite and I torque them to 5ft. pounds (that's not much!). The case warps very easily. Pick your torque-converter rebuilder carefully; A majority of the E40D "comebacks" have been converter related. One last thing; This is an electronic "90's" transmission . . . clean the case and all the parts WELL, and treat the trans with care upon assembly and disassembly; "We are technicians, not grease monkeys."
*ATSG stands for Automatic Transmission Service Group. The shop I am employed at belongs to this group. I recommend them highly.
Written by Ken Bachellerie. Copyright © 1997. All rights reserved. Do not duplicate or redistribute in any form, without permission from the author.