I sometimes get a clunk sound when i am at a very slow speed then accelerate....its almost as if it is between gears or something...i though i had heard this was a problem....i am taking my truck in today and was wondering if anyone else has had this problem and what the problem is and how it was fixed so i can explain it to the service shop today so they dont give me the run around....thanks

 

Yep. I have it too. When I am driving or coasting at about 15-25mph then accelerate I hear it.

 

I have the same thing. Almost like the transmission isn't in a gear at all then slams down.
I've also got a clunk back in the diff as well.

 

My truck does it to mostly when I im heavy traffic at a 4 way stop I have to go throough on my way home from work. The inching up and stoping over and over again makes very anoying when it does it.

 

I was haveing the same problem. To me it was like the driveshaft was sliping on acceleration. Ford gave me a new driveshaft. I think It was something to do with the rear driveshaft not lubed wien it was built.

 

See this thread. I also have the same problem.

https://www.f150online.com/forums/sh...d.php?t=263570

 

I have had the brakes redone,new driveshaft new rearend new yoke and new pinnion it still does it goes back wednesday

 

mine does it too, drives me nuts.

 

another victim here

ive noticed the tranny doing other weird things occasionally as well. sometimes when doin a 3-2 downshift at around 40 mph or so it will act like it wants to go back into 1st and rev up, even though its going too fast to go into 1st. it will then go back into second...

i just hope the thing doesnt doesnt blow up on me too soon....

 

An independent mechanic once told me my clunk ('02 screw) could be caused by the engine idling too high causing the drive shaft to bind and not slide back and forth smoothly until the brake is released at a stop light or stop sign. He said the only way to slow down the idle was to replace the oxygen sensor because there was no other adjustment. I didn't do it and have been living with the clunk for years. Does this seem like a possibility to anyone?
Billt23

 

Ok I recently bought an 08 Super Cab 4x4 with 23,000 ( I know it's under warranty just looking for info to help dealer if need be). Once in a while I have this exact same thing. I notice while going up a hill, I let off the throttle for a turn then mid way through the turn I lightly roll into throttle and get what I think is a harsh down shift that makes a clunk. It almost seems to me the truck is in the middle of an up shift then gets "confused" and down shifts. It has done it at the same spot a few times. I worked at a dealer for a few years from 2000-04 and I know usually there were TSB's to update the PCM for concerns like this.. Are there any TSB's for PCM reprograms on the 08 for this issue?