Another E4OD question

quickster · Mar 21, 2017

I've been noticing for the last few months that while running at least 40mph the trans will either drop 200 rpm or go up 200rpm. Not constant, but once I get above 65 it stops. I replaced the torque converter last summer, so I don't think that would have anything to do with it. Almost feels like it's dropping down a gear then going back up. But it's only that little bit. Anyone have an idea what the cause might be? Or maybe I don't want to know? I've been good to this truck and I'm hoping it's not getting ready to take a dump on me. Thanks

FORDF250HDXLT · Mar 21, 2017

Your converter is unlocking when it shouldn't be.There are a few things than can cause that.If it's not acting up above 65 then my first guess would be a failing FIPL/TPS.When was the last time you've replaced it? They're supposed to be changed every 50k miles.You can see how to set it here;

Whats a FIPL?

quickster · Mar 21, 2017

I just replaced it 6 months ago. I just did the pump and injectors. I was thinking maybe it was unlocking, but what would be the cause?

quickster · Mar 21, 2017

And the voltage was set dead nuts.

quickster · Mar 21, 2017

Did some searching. Could be my brake switch, bulb filament, tach wire, or loose plug on tps. We'll see.

FORDF250HDXLT · Mar 21, 2017

Yeah,also possibilities.The fact the converter remains locked at 65 MPH or higher,helps narrow things down.For example,a bad brake switch or bulb don't get better by going 65 mph or faster,nor does a bad connection become good at speed then bad at low speed.
TPS/speedo/tach are prime suspects in this case.

quickster · Mar 22, 2017

So I go out this morning to check the TPS and tach connections. I have the TPS plug halfway out and the cover pulls right off of it. Lesson learned: hold the part with one hand as you pull the plug with the other. So I epoxied it up, some dielectric grease, and gave it a test run. It's ok, but didn't have time for the highway.
My wires from the tach sensor are fine. Pulled it out and it was clean. I used the cruise the other day so the bulbs and brake switch must be good. Anyplace else to look?

Mike_42 · Mar 22, 2017

I'm having this same problem except it only does it 65 and above. Also only does it when maintaining the same speed for little bit, the rpm's will go up 1-200 and I can feel it, speed doesn't change or anything.

trackspeeder · Mar 23, 2017

Transmission Range Sensor can cause that problem.

quickster said:
So I go out this morning to check the TPS and tach connections. I have the TPS plug halfway out and the cover pulls right off of it. Lesson learned: hold the part with one hand as you pull the plug with the other. So I epoxied it up, some dielectric grease, and gave it a test run. It's ok, but didn't have time for the highway.
My wires from the tach sensor are fine. Pulled it out and it was clean. I used the cruise the other day so the bulbs and brake switch must be good. Anyplace else to look?

Transmission Range Sensor.

quickster · Mar 23, 2017

Thanks Trackspeeder. I will check the connection tomorrow. Today I found one plug barely together between the driver's fender and coffee can. Also checked and cleaned the plugs underneath the master cylinder. But when I got to the plug that goes to the solenoid pack behind the heat shield, I found some corroded pins in the plug. The rubber seal inside the trans side of the plug was torn in half as well. One of the tabs that secures the plug broke--the one against the trans. The ouside tab has been gone since the PO. So now the male plug has no way to lock to the female side, and the rubber seal in the solenoid is gone. Is it Magyver time?

trackspeeder · Mar 24, 2017

You can get a replacement pigtail for the solenoid pack at NAPA or fleabay.

Broken connectors are very common because people like to use screwdrivers to release them. Always squeeze the tabs and pull to release.

quickster · Mar 25, 2017

I fixed the lock -unlock issue. Must have been the plug going into the solenoid pack. There were a few green pins in the plug, but was able to get them clean. Shot some brake cleaner in there, blew it out, loaded it up dielectric silicone, and shifts like it should. Took it out on the Parkway and no unlocking. My tach needle is still screwy when cold, but it seems to have no effect on shifting. Keep the plugs clean!

raydav · Mar 30, 2017

I long ago put an LED in the cockpit from each solenoid. Light on is solenoid powered but not energized - they are energized by grounding the low side. I too have had shifting issues due to intermittent connections. But the LEDs can give me a definitive reason for the issue.

FORDF250HDXLT · Mar 31, 2017

That's odd.I normally say to start with that but only happening over 65mph threw me on that one.Not sure I understand that one but cleaning up/replacing a bad bulkhead connector sure is good maintenance.

Mike_42 · Mar 31, 2017

quickster said:
I fixed the lock -unlock issue. Must have been the plug going into the solenoid pack. There were a few green pins in the plug, but was able to get them clean. Shot some brake cleaner in there, blew it out, loaded it up dielectric silicone, and shifts like it should. Took it out on the Parkway and no unlocking. My tach needle is still screwy when cold, but it seems to have no effect on shifting. Keep the plugs clean!

Just did this as well and fixed my RPM changes at high speeds.

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Another E4OD question

quickster

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