1990 7.3 idi e4od transmission issues

KyleJamesBrockman

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Ok this problem is a doozy so I’ll try to explain best I can and hope somebody knows these transmissions well enough to point me in the right direction.

To start the truck is a 1990 7.3 idi automatic 4 door bronco. It’s all factory. No modifications except for an hd billet torque converter. I had the transmission rebuilt this fall. Transmission works great mechanically.

Since the rebuild, the tach has not worked (not a tach sensor issue.) When it rains heavily or I take the truck through a car wash, however, the tach works for a few miles. When the tach is working the transmission operates strangely. Soft shifts, erratic shifting between 3 and od. Etc.

Since the rebuild, when I was towing heavy for a long distance the truck would not shift down to 1st when I stopped. Could not do it manually either. This began happening more frequently, then stopped for a few months. This issue is back now, and the truck never shifts down to first. Not even when I start it up.

Also the truck was leaking transmission fluid out the top vent one night. Has not happened since.

I know that was long but thank you for reading. Any help is greatly appreciated. Y’all have a good day and good luck with your projects
 

DaveBen

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Who did the tranny rebuild? Have you mentioned these symptoms to them and what did they say? I hope you got some sort of warranty on the rebuild.
 

Nero

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If you can't manually pull it into first with the shifter, either the shifter is out of adjustment, or there's something really funky going on with the valve body....
Is your o/d light flashing?
 

KyleJamesBrockman

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A good shop near me did the rebuild. I do have it warrantied but I thought it might be electrical so I wanted to figure it out myself as it’s my only truck running right now. Od light is not flashing and the shifter is adjusted perfectly
 

trackspeeder

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Check the TCM for water damage. (inside left kick panel)
The TCM needs a good tach signal in order to work correctly. No signal or erratic signal will cause shift issues.

Starting in a higher gear is usually no power to the TCM. Check the TCM relay. (under hood left fender)
 

ZachW98

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@KyleJamesBrockman did you ever figure out what was causing the issue? Not sure if we have the same problem but I'm running a similar setup 89' Bronco with the 7.3 idi diesel and e4od. Tach all of a sudden doesn't want to work and has intermittent shifting issues but it'll drive just fine sometimes. The main difference we have is I ordered a rebuilt tranny from here https://reman-transmission.com/transmission-codes/?code=E4OD and let a local shop do the install for rather cheap I might add.
 

BossHog

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My issue is slightly different but similar symptoms. I lose my lower gears after shifting up. If I put it in park when I come to a stop I get my lower gears back. So I guess my issue is no downshifting. I talked to a builder that was familiar with the E4OD and he said the speed sensor on the back of the tranny should be tested. Mine has soft shifts too which I think is just an early shifting problem. That might be a TPS adjustment. There is a lot of play on those TPS brackets with lots of room for adjustment, also lots of room to be slightly out of adjustment. That is where I am starting. Testing the speed sensor on the tranny and playing with adjustment on the TPS. There is a way to test the TPS but I don't have the equipment for that.
 

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