Hello everyone new to this site. Please. Be patient as I'm new to fords in general I have literally searched google for days trying to match my problem. A lot of posts are very close or give me good advice where to look etc but I'm stumped. My tranny guy refuses to actually maybe think there is another problem besides oh give me a 1000 dollars will rebuild it. So here is the story and issues. I. Bught a 1989 f superduty with a 7.3l diesel motor automatic with a e40d tranny. Has a push. Button overdrive on dash. Previous owner claims was rebuilt. Of course no receipt. Drove 100 miles home not one problem. Took out to store again and again drove no problem. Next day I hooked up a back up camera. And cleaned up some wires the guy had on floor for lights etc . Started it up and checked fluid noticed was a quart or so low. Filled up with mercon like dipstick calls for and took off down the street. I have drive and won't shift from first gear noticed if I shift to second manually all is well. I also have reverse. I. Noticed my tach and speedo are both working fine and the od light is not flashing like other posts stated. So I get home crack pan and do not notice anything more then typical fine dust on magnet. And solenoids and valve body look brand compared to other areas etc. new pan gasket and new fluid same problem. So after researching I tested my fipl sensor and it checked out with in specs. Also tried to see if getting any codes. I do have the eec connector but the little one wire test port is missing. So no codes. Now. Checked all fuses all are fine. tested the eec relay and does not seem to send power or click when key is on I manually put a wire to relay from fuse box so it now has power when key is on but still same problem so I'm finding a problem already with the eec relay not having the power with key on. I have not checked the speed sensor or tach as my gauges are working fine? All connectors look ok. I even checked all fusable links by passenger battery and all are ok. Only thing I have not checked now is the range selector on side of tranny. I guess I can also check if solenoid pack is working just seeing if anybody had this problem I'm really thinking my tcm may be fried I refuse to believe the tranny is broken when it drove fine until the time was ready to drive. Even told tranny guyI know trannys will go out but usually noticeable not drive fine and break once parked. and ready to take off. all other posts don't have this problem with no light blinking etc etc. so where do I go from here. I am thinking solenoid but I have first second and reverse. At least second if put in manually. Tranny guy said it wouldn't be a. Blocked valve if I have reverse etc I do believe him on that part. But I'm lost and stumped and. Believe it is electrical vs mechanical on how it only happened after wiring a back up can whether this is related or not but. maybe computer fried out of no where etc this would allow engine to run but tranny control be broke especially after eec was not clicking when key on. The relay is fine itself it just not clicking on it's on. So hard wired it in to power. So now relay should be fine etc. just weird any input advice will help sorry for the two page story. Thank you again in advance

 

Yea, it's best to simplify and avoid writing books lol.

It sounds like the sensor on the pump could be the culprit, but you said you checked it? How?

Could also be the Trans controller, you could take it apart and look for busted and leaking capacitors and such.

 

You have a tranny guy who will rebuild and E4OD for only $1000? Never heard of that. Maybe he meant that's how much for me to pull it and take it apart and then tell you the real price?

I am suspicious of the wiring changes you made since that's when it started acting up.

 

Yes my trans guy said long as no further damage then a snap ring and materials should be a 1000 bucks. I would have to pull it though. He had did a 700r4 for 650 for me and ran great after. Now the tps or fipl I just followed the how to all over google. 5.0 volts were being sent to it. Back probed and seen 1.1 at rest and 3.8 at wot. Did not test while running. Was key on only. And yes I do believe after I did some wiring is suspect. I blew the fuse for cigarette lighter. Doing so and changed etc. I can remove the computer today and take a look inside.

 

Yeah it sounds electrical.I dunno what to think about a trans shop tossing out 1,000 bucks and just hoping it sticks lol.I might not want to deal with that shop.Pure speculation based on so little.

 

So it worked fine until you started messing with the wiring. I don't know what you did, but you changed SOMETHING with the wiring that caused this. If you rebiuld the trans you'll have a fresh rebuild that has the exact same problem.

 

So today removed computer all looked ok. No burned or broken anything. Cleaned contacts. Re wired every wire in rear clean and direct from factory harness all lights work but back up lights. Also. Another story guy said when he replaced trans it would not start so hooked up the push button it currently has now. So mlps. Is my suspect. It controls start and. Back up lights. So read about it says also controls up shifts. So took part off and Olhm tested it and I get nothing. No where near what the ranges should show. Checked every pin in different orders in case got the wrong way to test. Son now I'm thinking I have a ****ty mlps. Will buy tommorow and see if cured. But. Almost excited with this new development

 

So no expert but I tested with part off the vehicle. I'm reading now that needs to be tested while on connector. Which I need to redo again lol. So never mind I'm excited possible news

 

So I hate posts with no results. But I fixed truck. I re did all back up wiring etc. and still same problem so I bought new mlps sensor. Now back up lights kick on. I can start truck with key again and eliminate a push. Iron guy put on. And. Ow truck drives and shifts 100 percent again. Did not have much help from other forums etc. so just to clarify because everybody else's posts on google suck. But if mlps is bad. It will cause a limp mode condition. Meaning only 1st reverse and manual second. Thanks everyone

 

$40 bucks sure beats paying a thousand. Now you can call that trans shop and tell him that he doesn't get to eat for free this week lol.