I have a 2007 F150 4.6L 4X4 Standard Cab Short Box Automatic with 60,000 miles.

I had a problem with the transmission where it would clunk at highway speeds when letting off and reapplying the accelerator slightly (not punching it to pass, but just normal operation). I also experienced a "shudder" and clunk when coming to a stop as I passed down throuh 25 mph. It wasn't U-joints or the spline grease problem, and Ford drcided to replace the tranny with a Reman unit at 58,000 miles. (Replaced transmission and torque converter under warranty.)

No more clunk at highway speeds, but am still feeling shudder/clunk at 25 mph only when slowing down. I complained to the dealer and after driving the truck, the Ford engineer says, "normal stack tolerance". Bull.

Didn't do this when the truck was new, and I've driven others with the same engine / drivetrain combo that are much smoother rolling to a stop. Again, no problem with the u-joints or spline - I do not experience any problems when accelerating from a stop, just slowing down.

The problem goes away when I disable overdrive.

Any thoughts?

 

its your converter locking and unlocking. mine did it and when i got my edge programer and had it display the gear im in it also tells you when you converter locks and unlocks and that clunk is when it locks and unlocks quickly. the shudder is also in the trans, ive been told to get a friction modifier to help it bite but mine went away after a few thousand miles and has been fine for a while

 

So I programmed my Edge to show gear and converter lock, and it turns out the clunk I feel is the 4-3 downshift. That's why I don't feel it when OD is disabled. Torque converter lock and unlock is fine - no problem.
Back to Ford - again.

 

have you changed your shift points and could the downshift be off or trying to do two things at once?

 

No, stock program.

 

than maybe try to change it around and see if it stops. move the shift firmness down or move the downshift rpms down. try diffrent things or go to the dealer and tell them when its doing it.

 

My F-150 Supercrew cab 4x4 has a similar problem. I let off the gas, slow to make a corner and reapply normal acceleration to get back to speed and the engine revs and clunks into a lower gear. This is very annoying and when someone is riding that doesn't know my truck says, "What was that?" Coasting with no pressure on the accelerator does the same thing. Its like the truck forgot what gear it came out of and now searches for a new lower gear. Have taken it in at 25,000 and they lubed the differential. In again at 40,000 same. This time they said this is a normal sound and you'll just have to get used to it. "It's within tolerance." they tell me. Bull. Now I have 56,000 and warranty goes out in Oct of this year or 60,000, whichever occurs first. I am going to take it back in, but I need the technical "buzz" words to get the right action on this sick trans. Any help out there????

 

I would definitely not let the dealer know that you have that edge on it (and definitely wouldn't tell them that you have been messing with the shift points/rpms with the edge). They will blame the edge for your tranny problems. I would, however, complain until they do get the problem fixed. At some point in time, these trucks got a reflash of the computer system. Make sure that they have flashed it to match the tranny they installed.

 

Clint, hopefully he's already solved the problem. The thread is a couple years old.

Stewart

 

+1 They frown upon any aftermarket modifications and will not cover your warranty because of it.