4r100 tc unlocking/locking in OD

[UNBREAKABLE]

So, I'm picking off gremlins one at a time...I've got my engine under control, now it's time for the trans. First off, I have no clue as to the history of this trans up until 2,000 miles ago.
Trucks specs
1999 F550
2wd
7.3
4r100
205k on the ticker

I was driving the truck yesterday and the trans started acting funny in OD. Under power, no trailer load, not jackassing around the trans would unlock and lock the torque converter(only on OD). I had it scanned...NO CODES. No TPS or Cam sensor(truck just had the cam sensor replaced under recall).

Any suggestions?

[freeride707]

did you ever get this issue resolved? mine is doing this too, im thinking either TPS or a speed sensor,

[Coalrolla9740]

Same fluttering and gear hunting. Sometimes it will function fine. I had flashpaq 1855 tuner and put everything back stock and replaced entire accelerator pedal assembly. Still intermittently given me h*ll. Problem peaks around 40-60 mph area. Hills I used to easily pull with cruise on at 65 @1850 rpms , it's now downshifting and running between 2200-2900 range.

HELP!!!

[freeride707]

ok mine goes away when when i accelerate or decelerate but it is only in the 40+ mph range. Mine doesnt hunt for gears but just unlocks and relocks. I talked to Brian @ BTS and he said its a tuning issue or something telling it to unlock. I ran mine on an Auto Enginuity and the computer was telling the TC to unlock, so now i need to find why its telling it to unlock. Im guessing its the accelerator so thats where im going to start.

[UNBREAKABLE]

Nope, haven't found my issue yet.

[99dieselsmoker]

i have a 99 250 with 450k on the ticker n its doin the same thing lock unlock in od just up a light grade... in 3rd it will hold...

[Lunatic250]

I have the same issue TC locks and unlocks around 40mph,plus my o/d light turns on only when in park,R and N. It goes out of overdrive if i press the button while driving but light wont turn on. Im wondering if its just out of adjustment

[99dieselsmoker]

ok i got to the bottom of my troubles im at 449k n i hooked my scanner up as i was pulling the hills to work one day n discovered the converter was actually slipping n the worse it slipped the more likely the computer was to disengage the clutch. thats why it seemed to only cause trouble going up hill...
unbreakable id be willing to bet ur issue is the same as mine

[99dieselsmoker]

Originally Posted by Lunatic250

I have the same issue TC locks and unlocks around 40mph,plus my o/d light turns on only when in park,R and N. It goes out of overdrive if i press the button while driving but light wont turn on. Im wondering if its just out of adjustment

its been my experience that a flashing o/d light means trans trouble some slipping or a bad sensor possibly if its flashing it threw a code

[Lunatic250]

yea but my o/d light doesnt flash

-I kept on looking and playing with the lever and noticed that if i pull the lever towards me it will turn on the o/d light on so im beginning to think its a lever/switch assebly issue. Iv been told the switch and shift lever assembly has been known to go bad pretty often cause of wear