Hello all. Alright, so I've been researching online for the last couple of weeks, found a lot to help me try and sort out the issue I have with my new-to-me 2005 F150 Screw FX4 5.4 Triton with 165,000km on it. I'm pretty sure it has the 4R75E, the door tags list "B" for the transmission and from what I can find the B in 2005 meant the 4R75E.

Here's the issue (which I've read many places), I have a shudder when I apply very light throttle after approx. 50kph, so generally speaking I think it has to be in at least 3rd gear for it to happen. I can apply heavier throttle and it will quit, I can let up and it will quit. But I can also make it do it on command, as long as it's warmed up after about 5minutes of driving. As many describe it online, the first time I felt it I thought I was going over some rumble strips. It does feel like it is getting a bit worse as time marches on here (about 2 weeks and maybe 1000km +or-)

I've read that it could the COPs, the torque converter, something deeper in the trans, or even the CATs.

So, I'm driving the other day on a 4 hour trip the mountains here, the shuddering is happening like clockwork, and suddenly I get a "Trans Fault" on my odometer with the OD flashing as well. Interesting, ok, my guess that it was the COPs was wrong. As well though, while the fault was showing, the thing was perfect... for the next 2 hours, until I stopped for gas, the thing behaved like it was a brand new little baby. Started back up after gassing up, the trans fault was gone and I had my shudder back. Ok, so bad news, but not really because now I knew what it was and I wouldn't be wasting money in the wrong area.

When I got home I put my bluetooth OBD reader on it and got the P1744 code which is "Torque converter clutch solenoid circuit performance". So my question is... would it be as simple as changing the solenoid out and flushing the transmission ($350 at the local shop in my small, very remote town) or do you think I should just bite the bullet and change out the torque converter at the same time? If I flush the tranny, change out the solenoid, and change/rebuild the TC, would that be changing or fixing everything that code could generate on, so I'm most likely gonna be fine?

If that code could also easily have something to do with other issues deeper in the transmission then I'm not sure just biting the bullet with the TC now is the smartest thing to do. My own logic tells me that changing the fluid and changing the TC "should" fix any possible issue. Am I fooling myself?

 

If you have 165k km, it's due for spark plugs. I'd do those first.

 

I'm having the same problem but no code.
I remember reading that the TC solenoid wiring harness is in a bad place and rubs thru and the wires arc to ground, hence the shudder when engaging or disengaging. I was thinking of doing a fluid exchange and if that didn't help look for the bad wire.

 

Your definition of a P1744 is incorrect, it is not a circuit fault.

The correct definition is "The PCM picked up an excessive amount of TCC slippage during normal vehicle operation" with a symptom description of "TCC slippage/erratic or no torque converter clutch operation. "

 

I've also found that P1744 is "Torque Converter Clutch Stuck in Off Position" (here and here)

So what I've done is I've ordered a torque converter, TCC solenoid and the wiring harness. I think if I change all that, that should clear up any problems most likely??

I may have been stupid (I'm hoping not, but I've proven to myself over-and-over the opposite) I ordered a "low stall" torque converter because I plan on pulling my 24ft travel trailer. I assumed, from my reading and self-education on the subject, that I should be able to just swap a standard TC to low-stall TC without any modifications or programming required whatsoever because all it does is just lock up a bit sooner, correct?

 

Why didn't you do the spark plugs first? Cheaper and easier, and you are due. You have the exact symptoms of a low grade misfire, caused by worn out spark plugs or weak coils. In spite of the code, your TC may be just fine.

 

Well, the reason why I didn't suspect the spark plugs later was because once when it threw the code (P1744), which has to do with the TC and transmission, etc, the truck drove like a dream (as I mentioned above). If it was a low grade misfire when it threw the code it still would have missed... instead the problem was gone.. for 2 hours of driving in the mountains, smooth and perfect. Once I turned off the engine to fuel up, and the "Trans Fault" was gone on restart, I got my shudder back... pretty convincing evidence to me that it was not a low grade misfire but a Torque Converter lock up issue.

 

The data I gave you is right out of the factory service manual for YOUR truck. If you want to believe some random internet search results over the factory service manual, go right ahead.

 

My apologies, I wasn't trying to second guess you. You hadn't mentioned where you had got the code information from, so I was just throwing other information out there that I had found. Now that I know you got it directly from the manual for MY truck obviously that ends it... Before knowing that, your information was just as authoritative as the other info I had found. Thanks for that clarification, definitely helps.

 

Well, changed all three... the Torque Converter, TCC solenoid, and the solenoid wiring harness... and the truck now drives like dream. No vibrations or shudders whatsoever, hopefully it stays that way!