Hopefully I can get some ideas here on this problem that Ford can't figure out. 2003 Ford F250 4X4 w/ 6.0L and Torqshift trans 68,000 miles, stock.
The truck has some issue with what I will call a dead throttle most times when shifting between forward and reverse. You shift into reverse and back up, put it back into drive and try to accelerate as you normally would ease into the pedal and there is no response immediately. After a second it will accelerate but it lunges forward. Sometimes it will do it going from park to drive but not as often as from reverse to drive. Ford went as far as replacing the trans with a Ford reman unit which made no difference. I was told by a tech that there is a sensor that will not allow the trans to switch gears between forward and reverse until a certain very low speed is signaled. Is there such a thing? It is almost like I have to push the accelerator down to a certain point to trigger a response. Then at that point the pedal is down farther than you would normally push it when easing into a forward direction causing the lunging. Some sensor on the pedal? Very frustrating when plowing!! Please help!!

 

there are 3 swiches on the pedal you have app1, app2 and app3. its a self coralation divice and if it fails the only thing that should happen is you will be stuck in IVD mode. I would think based on that the pedal is not going to be your issue.

 

If your Ford techs are stumped on THIS problem, it's time to switch to a better Ford dealer!

 

Maybe this applies ........

Harsh or Delayed Forward or Reverse Engagement:
This could be caused by a sticking line pressure control (PC-A) solenoid. Typically the line pressure will be fluctuating wildly (up to 500 PSI!). To service, first remove and inspect the external cooler line filter. If it contains fine gray metallic debris. If metal is found, the source is most likely a defective reverse planetary pinion shaft that is coming out of the carrier and contacting the case or adjacent components. The transmission will need to be disassembled and repaired as needed or replaced. Broadcast Message 3250
If little or no debris is found replace the line pressure control solenoid with P/N 4C3Z-7G383-AA. Broadcast Message 1586/SSM 17874/18051
This repair will require removing the solenoid harness, so a new harness sealing o-ring (P/N 3C3Z-7Z276-AA) will need to be installed. In some cases the solenoid body will need to be removed from the trans to remove the harness and solenoid. In this case the solenoid body gasket (basic P/N 7C155, trans tag number needed) will be needed as well. Note: Do not loosen the 10mm head bolts on the solenoid body. Only loosen the 8mm head bolts.
If the solenoid has been replaced and the condition it still present, suspect a contamination issue of the solenoid or a sticking pressure relief valve.

 

hey mark the op got a reman unit. the megatronics comes complete with that. but still good info.
heres a thought as well ..... some slack in the x-case will cause this concern and some of that is just the nature of the beast with a 4x4

 

if i was troubleshooting the bigger allison trannies i'd say your turbine speed sensor was gunny-sack.could it be something as simple as a vehicle speed sensor?.i'm sure they checked that though.does the torque-shift have sensors such as turbine speed?.

 

has both tss and oss sensors. but bonce again both are validated by the abs module and aginst the vss and left/right wheel speeds, if that were the case then we would be most likly looking at improper gear ratio codes.

 

Yes, I know I need to find a new dealer. Here's another bit of info. When my old tranny was still in the truck and they were trying to diagnose it, the tech said that when he was testing the tranny it "PEGGED HIS GAUGES" I believe he meant line pressure. New tranny still has same issue, so are these hints making any sense. Is there something external of the tranny that would cause this? THANKS FOR ALL THE HELP!!!!

 

the only way to know that is if you know the differance between what the pcm is asking for and what the transmisson is doing. its still possible that the pc-a in the reman unit is no good. not the first rebuild I would have heard of with an issue. there is a wire harness from the pcm to the trans and an internal one in the pan that can also cause like issues if shorted as well.

 

What should I check out? Where would you start? Would like to solve this myself as the truck is now out of extended warranty. Thanks again.

 

the reman repair should be good for 12/12 so if you are under that then you may have soem hope.
as to were to start... Im not a trans tech, im just do the engine work and have to know when to send it to the trans guy or when it my issue to deal with. With out a scan tool that allows transmission mointering and such you will have very limited success.

You can try a new pc-a if you fell like tossing a part at it.

 

This is what I was thinking also. Well said cheezit.

 

I should have said in the last post that the truck still has the same problem with the "dead pedal" even after the re-man was put in. I kind of made it sound like it still was "pegging" gauges as it was during the diagnosis. Rebuilt trans or the original, it still has the dead pedal, that's why I'm thinking outside of the trans. What do you think, I'm picking you fellers brains here, can you tell?

 

have you look at the egr valve to see if it slightly stuck open? do you know what the egrvp value is? it sould be around .79v koeo up to about 1.0v

 

egrvp? Help me out here. Key on engine off, that I get. Egr can cause trans issues?