E40D Help Please?

[Titojeep]

Guys, need some help again but this time with my trans. At highway speeds specifically 60-65 mph where I normally run my transmission is starting to rev up as if it kicked out of overdrive. If I let off the accelerator it will go back and hold again. A couple of times it would rev up (shift out of OD) real quick and back again. My O/D light on the shifter does not light up so I don't think it's providing a code. Any ideas? Please see the additional comments on the truck:
248000 miles on engine( Non abused truck. got the truck at 199000 miles on sept 2009)
50,000 on rebuilt trans. (tow a 4000lb camper about 3 times a year. Truck sits most of the time, but have used it as daily driver last 3 months due to main vehicle being broke down. During this 3 month period I've put on 2500 miles a month)
Problem just started 2 weeks ago and has happened about 10 times with 5 of them being yesterday on the way home from the airport where the truck sat for a week.
Fluid level is good, color is not burnt, does not smell burnt, and no leaks on transmission.
Any help would be greatly appreciated.
Thanks

 

[trackspeeder]

Check the TPS. Most likely it is out of spec.

 

[LCAM-01XA]

About 300 rpms revv-ups while just cruising along? She's not dropping out of OD, she's unlocking the converter cause she can't decide if she's at idle or at cruise. Like trackspeeder suggested check TPS voltage sweep, look for dead spots around mid-throttle.

 

[Titojeep]

Thanks. I assume, if I look up how to check it and it's not correct, then I will need to replace it? or is there an adjustment?

 

[LCAM-01XA]

There is an adjustment and you'll be using it when setting up new TPS. But they don't just fall out of adjustment usually (unless bolts were left loose from a pump swap or something), and if it did vibrate itself out of adjustment then you'd be seeing shifting problems in all gears, not just OD. What I suspect happened is the part of the TPS the lever arm uses most while at cruise simply wore out with mileage on truck and now you have a dead spot there.

How to check it:
1) run engine till it's fully warmed, then kill it.
2) stick a paper clip or a safety pin in the hole of the TPS connector where the middle wire goes in.
3) hook up positive (red) lead of multimeter to said clip or pin.
4) hook up negative (black) lead of multimeter to driver side battery negative terminal.
5) turn ignition on (do not actually start engine), take voltage readings with multimeter.

At idle position you should have between 0.9 and 1.2 volts. Now move the pump throttle lever by hand to wide open throttle, it should give you between 3.8 and 4.5 volts. Now check sweep by slowly move the lever between idle and wide open a few times, watching the voltage change - the numbers should gradually increase from idle to WOT and then gradually decrease on the way back down to idle. If you see any sharp jumps or drops in voltage, that's a problem spot inside the TPS.

If you are to replace the TPS, remember idle voltage of your current one - then when you drop the new one in set it to the same voltage at idle and trans will shift the same as now (minus the OD lockup drop issue) like nothing ever happened.

 

[Titojeep]

Thanks. I'll give that a shot today after church.

 

[Titojeep]

So I checked the lower, upper, and sweep as you noted and found nothing out of the ordinary.
Idle position 1.0V
WOT position 4.0V.
Sweep, multiple times, no missing readings. The meter went through the range without any skips, or quick changes. Engine is warm, and Idle solenoid was not engaged.
Any thoughts???
On a related note, I left out another detail on my initial description. The fuel system (pump, injectors) were replaced at 210,000, therefore I assume this sensor is also new at that time as it does not have the appearance of being a 20 year old sensor.

 

[trackspeeder]

Turn it up a hair. Then test drive it.

 

[Titojeep]

Thanks. I'll try that next. not sure if it's related, but as I was looking over things closely I noticed that the two wire sensor on the oil filler housing has exposed wires. I assume from age, the insulation is pulled back. The conductors were laying down against the metal part of the sensor. I haven't had a chance to look into this, but I seem to recall reading a post in the past where someone experienced shifting problems due to this sensor? I taped the conductors and went for a test drive and did not experience any issues. It wasn't a long test drive, so the real test will be tomorrow on the way to work where I'll have 52 miles and about an hour to see if this helped. I'll post my findings. I also took a few minutes to check the two other plugs on the side of the transmission. The sensor on the shifter had a really clean plug and appeared to be in good shape. The one on the exhaust side (with the heat shield) looked good, but I didn't pull it off. Ran out of time so I plan on doing that next as a precautionary step. If I have negative results tomorrow, then i'll bump it up as you suggested, I assume up to about 1.1V?

 

[LCAM-01XA]

Bare wires on the tach sensor on the IP gear housing with oil fill neck can and will confuse the TCM. Good chance fixing them also fixed your initial problem. Also good call on checking and cleaning the transmission connectors, I've had the one behind the heat shield get wet and act up.

1.1V on the TPS should be good, try it and see how you like the shift schedule and firmness.

 

[Titojeep]

Well, went back and forth to work today (115 miles round trip) and no problem with the TC unlocking. Will give it another day or two, however it looks promising. I'll post my results. Thanks again for your help.

 

[OLDBULL8]

Ya, I think ya fixed it. With bare wires on the tach sensor, the fan air will blow the wires around and short them out causing your problem.

 

[Titojeep]

It's confirmed. Several days and no problems. I appreciate the help guys. The problem was definitely the bare wires on this sensor. Have a blessed day.

 

[icanfixall]

We have another issue that will cause the torque converter to lock and unlod repeately. A burned out brake lite bulb. What happens is the burned filament contacts the trun signal filament in the bulb. Then when you use the signal you feel the lockup unlockup as the lite is blinking. Had this on my truck after the complete rebuild. I sure thought I did something wrong till a member here made that post. Another issue with the E4OD trans is the brake peddle switch. Be driving down the road in 3rd or od and lightly touch the brake peddle. That switch unlocks the converter and does it so when you come to a complete stop the engine wont die like forgetting to press the clutch on a standard tran at a stop. Also try coasting around 45mph or more and let off the throttle peddle. See the tran drop to idle positon. Now ever so slightly add some throttle. See the tach jump up. Thats the design on the E4OD trans..