1996 E350 based class C , 7,5L E4OD tranny

left home in Quebec for our winter roadtrip ,drove south on 87 for almost two hours , no issues !
then lockup started to act up,,,,,,,,it quits if I slow down or go downhill, and when it quits it might stay off for a while , so rpm goes up about 300 and tranny temp rises quickly
strangely ,if I put torque like climbing a slight grade it locks up ,and as soon as Îm on flat ground it goes off again ,

If I stop for refueling or 10 mins rest, it runs great for a while ,then acts up again

oil level checked !

we are now in Catskill walmart parking for the night
never had to face such problem before

anyone had this issue ?

 

This might be a question for the Transmission sub-forum here on FTE.

Good luck with resolving this problem.

 

Just another avenue to investigate, although with your issue being intermittent it doesn't seem likely. E4OD's (somehow) use a ground signal thru the brake light bulbs (without brakes applied) that allows torque converter lock-up. Simply changing to LED brake bulbs (without adding a resistor of some type) will prevent lock-up. BTDT went back to standard 12V bulbs. Only way I can see this being your issue was if one of your bulbs had a filament that was broken yet intermittently making contact still. Not likely but worth a look. Good luck.

 

Also check the brake pedal switch. A misajusted switch or one going bad, will many times send signal when hitting bumps or a change in pitch( up or down hill).

 

This morning, chilly , but no choice
found the problem : a wire that connects to the pedal brake switch was damaged grounding on metal ,,,,,,fixed it , goes great now !
thanks for the inputs , 🤗
Dan

 

^^Thanks for updating your diagnosis and repair----might be helpful to someone else in the future.

The advice about LED tail/brake lamps is interesting!

 

Thanks for the update. Glad it was that easy a fix for you.

 

I did it mainly for that purpose
it might help someone

 

That's how we learn. Anyone coming into the shop and complaining of tranny jumping in and out, first check was for brake switch adjustment. You would probably be surprised how many times it only needed to be adjusted. Something that almost anyone could do.

 

Incredible, Thank You!

1997 F250HD XL, 7.3L, E4OD, Turbo, extended cab, with 243,000 miles on it and has never been abused. Engine oil, fuel filters, transmission oil, etc. all changed and maintained.

Two weeks ago I switched from incandescent lamps to LED turn / stop tail lights and a couple of days later when I drove the pickup, it would shift normally and the converter would lock then just unlock with a 250 - 300 RPM gain and no speed change. I could make it relock by pressing down on the throttle and when I would stop accelerating it would unlock again, which was weird. Additionally the ABS light came on but replacing the ABS sensor in the rear end seemed to solve that, coincidence? In my effort to throw parts at it I've also changed the throttle peddle position sensor to no avail. I've been afraid it might be a transmission valve body or solenoid pack, or something other major in the transmission.

In the morning I am going to put the OEM bulbs back in and now, thanks to this thread, I full well expect your solution will be the answer the oddest problem yet with this pickup.

As I woul like to have LEDs for safety, I will to install enough parallel resistance to match the current of the incandescent bulbs and re-try the LEDs again. If the problem comes back, I'll have to go back to OEM lights. Also now I'm going to check the wiring at the stop light switch and will replace the switch for good measure.

Next, maybe even change the air in the tires, who knows?

This 1997 pickup is an odd duck in that it doesn't seem to be OBD1 or OBD2 even with the OBD2 port. The door hinges were 1996, tail light housings 1996. and many other components are just "order for both years and return the incorrect parts." It is registered as 1997 and the Vin and production date indicate it is a 1997. Guess there was a lot of 96 parts left over and were used...

This is a great forum and invaluable resource.

Thanks again,
Galen J.

 

First thing I check when the tranny locks and unlocks is the brake light switch. Many times the switch is out of adjustment or going bad and will make contact on bumpy roads or going up hills.

 

When the throttle is above a certain amount the PCM ignores the brake light input for locking the torque converter. So while you are accelerating you have the pedal far enough down to ignore the brake light. When you lift the pedal somewhat to stop accelerating it again reads the brake light circuit and unlocks the torque converter. This is normal operation.

Yes, that is a coincidence.

And that should fix the problem.

 

1997 F250HD 7.3 E4OD

After going back to the incandescent stop lights the transmission shifts just fine and the converter locks and stays locked.

I'll give resistor LEDs a try next.

I now know a bit more about the system and I'm relieved the transmission wasn't the problem.

Thank You!

 

Yep, the problem fixed with return to incandescent lamps. I've purchased the Throttle Peddle Position Sensor and Brake Light Switch, which I'll replace in a few days for peace of mind and a 26th birthday present for the pickup.

Next I'll check the data on the brake lamp circuit with it on OEM lamps then install the guaranteed "no fault, / no hyperflash" resistor LEDs (previous were not resistor LEDS, but seemed to work fine) and retest the data for noise and amplitude. With the fog and inclement weather we get, lights are very important...

Also nice to know the ABS was just a bonus fault and not associated with my LED creation.

Thank you very much for the knowledge, Appreciated.

 

Yes, this IS how we learn and it is a rewarding experience.

THANK YOU!