E4od tranny help!!!

[MaintenanceGuy]

Im not a mechanic nor do I claim to be. I'm just a do it myself guy or get my buddies to help. But bear with me if I don't make sense of things... I have a 1990 F250 supercab 7.3 IDI

So driving along around 45-65 the truck goes into OverDrive and when I try to maintain a speed it doesn't shift but it drops about 300rpms and back up 300rpms. I've replaced the VSS on the rear axle, the TPS on top of the engine, the neutral safety switch in the transmission, and the brake switch on the brake pedal. It still does it..

Then last night I figured out, while my foot is in the throttle going 45-65 it does it everytime I turn the right turn signal on.. help please!

 

[snicklas]

First, change the passenger rear stop/turn/tail light bulb. Try again......

 

[Robert walker]

My truck did the same Thing but it's when I turn on the parking lights it won go in to lock up but when the light are off it works great maybe sume input from the fellow idi guy's hear would be grateful for the help
P. S. I have a 1992 f250 7.3 idi n/a bone stock e4od trans

 

[snicklas]

To both posters,

The TECA (transmission computer) passes a small current through the brake light circuit. If the filaments in the bulb short, it confuses the computer. I would replace the bulbs, snd make sure the 3rd brake light (if equipped) is working. Also, LED "bulbs" cause problems also...... Simplest thing first, replace the bulbs...... If that doesn't fix it... Then we can peruse other troubleshooting.

 

[OLDBULL8]

Shot gun Maintenance can get awful expensive, 1147 bulbs are cheap.

The 300 RPM change is that the trans is shifting out of Overdrive, then back into it.

 

[IDIBRONCO]

Isn't that just the torque converter locking and unlocking? I would think that the overdrive shift would be more than 300 rpm different.

 

[david85]

To both posters,

The TECA (transmission computer) passes a small current through the brake light circuit. If the filaments in the bulb short, it confuses the computer. I would replace the bulbs, snd make sure the 3rd brake light (if equipped) is working. Also, LED "bulbs" cause problems also...... Simplest thing first, replace the bulbs...... If that doesn't fix it... Then we can peruse other troubleshooting.

^^THIS!!!

The E4OD is wired from factory to unlock the torque converter if you tap the brake pedal. Can cause all kinds or weird problems when rear tail lamp grounds or trailer wiring is bad too.

Isn't that just the torque converter locking and unlocking? I would think that the overdrive shift would be more than 300 rpm different.

Correct. Depending on engine RPM, powertrain load, and where you are relative to stall speed, you should see about a 300 RPM difference between locked and unlocked.

 

[rustygold]

Check all grounds on the stop trun on that side. This happen to me when I was pulling a trailer found out my harness ground was broken. Ever bump or trun to the right knocked it of overdrive and cruise.

Sent from my SAMSUNG-SM-G870A using Tapatalk

 

[MaintenanceGuy]

Ok so.. obviously I completely forgot I posted this on here and I haven't received any notifications that everyone had posted on this thread. Thank you for all your input!!! I will change my bulbs tomorrow! And see if that does it. I will post updates!!! Thanks again to EVERYONE!!!


One update I have,

I've noticed when I push the throttle to the floor.. it will shift from 1.....2.....3,4.........................OD.

I hope that makes sense?

Solenoid maybe? Or clogged filter? Or should I just take it to a transmission shop lol

 

[Thewespaul]

Posting a video would really help diagnose that, if possible

 

[MaintenanceGuy]

How do I upload a video? I can upload pics but it doesn't have an option for vids..

 

[Thewespaul]

Easiest way is to upload to youtube and just copy paste the link.

 

[Rolling_slow]

Did you replace the bulb yet? Like other posters have said the E4OD is a finicky beast. I had shifting issues not too long ago and it was a flat spot on the TPS. Voltage would drop to nothing at quarter to half throttle and cause all kinds of slippage. When you changed your sensors did you disconnect the battery prior?

 

[MaintenanceGuy]

I disconnected the battery before I changed all sensors, I also just replaced the bulbs. Still no change, here's the video of what it does.

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[MaintenanceGuy]

And this is what it does while cruising while it's in OD. It does this when I have my foot on the pedal.

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