2004 - 2008 F1502004, 2005, 2006, 2007 and 2008 Ford F150's with 5.4 V8, 4.6 V8 or 4.2 V6 engine
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I have a 2007 F150. It developes this bucking when the load slowly increases, like going up a slope/grade, only after the transmission is in lock-up (torque converter). I think it's trying to downshift while the converter is locked up. It BANGS when it does it. It does it between 40 and 45MPH unless I have OD disabled, then it does it around 35MPH. If I hard accelerate to Force it out of lock-up, then it shifts fine. At first, I didn't think it happens in cruise-control, but it does. Again, only after it is in converter lock-up and the load increases between 40 and 45MPH (accelerate slowly).
This happened so infrequently, that it would only happen in one place where I drive, and I don't drive there often. I thought I was hitting a curb in the road at 45MPH. That's how hard the bang is. And it would only happen there, because I was going the right speed, and slowly going up a hill.
Someone mentioned an electrical problem. Well, the heater control is erratic, too. When new, it would go from ice-cold to burning hot while crossing the 10 O'clock position on the temperature control. There was no median. I so finely tried to adjust the temperature here, very slight movements, but there was no warm. The dealer eventually changed the 'whole head' which he called it (the console), and it helped, but didn't fix the problem. Sometimes, bumping the electric window will 'move' this 10 O'clock threshold, sometime past the 3O'clock position (almost all the way hot).
The tranny Bangs are getting more frequent but softer. They've had it all apart before (dealer), even broke bolts and had to change the whole tranny case (same guts). Under warrantee. I've about given up on it. Run it into the ground, then never get another one. The dealer gets sarcastic. I have other dealer stories, with this same vehicle, if you're interested.
I've been chasing a shifting problem; while in TC lockup, bucks before it downshifts. I discovered something: Should the torque converter come out of lockup when I press the brake pedal (two-feet driving) ? This does not. The brake lights do work.. Alternately, when I know it's going to buck, if I release the throttle before the downshift, and get back on very lightly, then the torque converter is released, and it downshifts without bucking. Letting up on the throttle releases the converter, but the brakes do not. Does this have a mechanical MAF sensor that might be sticking?
Is there a module controlling the converter lockup? Someone mentioned disconnecting a wire that controls lockup, and that prevents the bucking..
Before getting all transmission trouble on us check the voltage available to the vehicle.
Voltage problems will cause erratic transmission operation.
I have a similar problem with mine. I have had the same bumping when accelerating from low RPM and slower speeds. Now I have an intermittant bump at constant low RPM and 40-50 MPH on level grade. I have 74,000 miles on it now and it just started with this. Very annoying to feel a small kick in the butt just cruising. Any suggestions would be appreciated. I am a first time user, long time reader on this forum.
Early on when I first got this new truck, I would feel a transmission bump when accelerating after making a turn. Ford says this is normal for an electronic transmission. So I've lived with for 7 years. Now its got me concerned with this new bumping at constant speed.
Last edited by Dudster; 01-31-2014 at 08:40 AM.
Reason: Add info
I have a 2007 F150 that HAD these issues. I finally took it to another dealer. They 'said' the computer said it had a bad coil. They changed it AND did a reflashing of the computer ($700!). It fixed the transmission AND the heater, which has never worked right. Well, the heater started acting up again after 2 weeks, but the tranny is still working correctly. It's been several months.
My Aunt has a Lincoln Navigator that has the same shifting problems I had, and they told her the computer said a coil is bad. She wants me to change the coil (which I think someone else did already - but it didn't fix the problem). I told her it's probably the computer and it costs about $700. I haven't heard from her since.
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