Hello everyone I'm new to the site. I have come across many threads on the site that refer to my exact problem. Which is the e40d trans. There never seems to be a final post of how the problem was finally fixed. My problem with my e40d trans is that there is no voltage to the red wire on the passenger side of the transmission. Yet I have power to the yellow wire on the drivers side, as well as power to the yellow wire to the computer. I"ve had a shudder in overdrive ever since I bought it, 1993 E350 7.3 diesel, Ambulance. So one morning I get in start it up and go to take off and it would not go into first on its own [ had to do it manually to shift thru all 3 gears to get it to move]. I got out of the truck to check the trans fluid and it was fine. At the same time I noticed the box marker lights were on, with the switch off, truck running. When I pulled on the light switch the box markers went out and the headlights came on. Everything had worked flawlessly since I bought it. I saw a post that LEDs might have something to do with it. I thought they were joking. I had replaced the marker lights six months ago with LEDs. I fortunately ran into a guy at a party tonight that owned a trans shop. He verified that this was a possibility, They had a fire truck in with all kinds of electrical Poltergeists. He said one of his smart guys figured it out the night before. He came in and changed the rear lights and that fixed the problem. The guy I met, knew a lot of the trans guys that I knew, and have used over the years. I had even had a few done at his dad's old shop. [small world] Any how, I had the trans rebuilt, with all heavy duty stuff, and a billet torque converter, put it in and had the same problem. I"ve pulled the computer out which I didn't know it had. [been a turbo 400 guy myself for a lot of years] I"ve checked the continuity on the harness from the trans to the main harness every wire checked out with 12 volts. I even took it out completely to visually check it and rewrap it. [no rub throughs anywhere, great condition.] Next ,I intend to pass voltage through main harness to the fuse box in the engine compartment. Now I have 3 books from the library to help me figure out where these wires go.
Any help would be greatly appreciated !!!

 

Welcome to FTE. Have you stopped by the Michigan state chapter and joined them yet?

 

Good morning! Welcome to the forum.

 

A `90s used Ford Ambulance in Michigan? I'd go checking grounds everywhere. If the grounding system is perfect, maybe try removing all the fuses that are unnecessary to have it run, then add fuses strategically until you provoke the problem.

The folks over in the "Clutch, Transmission, Differential, Axle & Transfer Case" forum might have some ideas as well. You might want to start a new post over there.

Welcome aboard!

 

The trans guy said it sounded like a ground wire. So did other people. Yesterday I was pulling every wire that would never be used again, in the process of getting to the main harness. To get to the main harness out, the brake booster had to be removed. It was getting replaced anyway because it was shot. Once I removed the booster, right underneath it there were two wires that looked like they had just been cut. Absolutely the hardest place to get to, I think the squirrel that built a nest on top of my motor, and filled my air cleaner with walnuts was the culprit. So the black with green stripe goes directly to the Transmission control relay. The other black one is hopefully the ground for the lights problem. Like I said, both of these issues happened at once. So I have a mountain of useless wire on the floor. I can't stand wires that are not being used anyway. I have a brake booster out that has needed to be replaced since I bought 6 years ago. Absolutely no braking power, and a freshly built trans that the torque converter was shot in anyway. Thanks for your advice, You were correct Sir !

 

LOL cool! Glad to hear you found it!

My 1999 F-53 V-10 4R100 has a similar issue. It tries to start moving in second gear sometimes. It's a common fault for the F-53, and is fixed by tying all of the grounds together so they all have a good connection. It's on my list for when the weather warms up, and in the meantime I can manual command it into first when needed. Your issue sounded similar.

 

definitely the grounds.