Folks, you might never hear the clunk if you always park your truck without moving it. As I said earlier, ALL vehicles are going to have driveline lash, whether you hear it or not (Ford obviously doesn't use rubber isolators to prevent it). If you let your truck move backward, the car moves a minimal amount (driveline lash) without the shaft moving, then the shaft starts moving in the opposite direction. When you start the engine after such scenario, the shaft moves quickly back to 'forward', taking the lash out, resulting in a clunk. You can easily check your amount of lash (very little), and duplicate a clunk, by getting under the truck and moving the shaft one way then the other. It'd only clunk when you move it the opposite way that the engine runs (meaning reverse). Those who claim to have a very loud clunk, it'd definitely not be the normal driveshaft clunk I'm talking about, which is just mildly annoying, not worrysome.

 

The only Ford I've ever drove that didn't have some sort of driveline clunk is a Mustang with a manual transmission. My wife's 15 Explorer even clunks sometimes on startup. My 18 F150 has a front end clunk on every startup but I'm almost certain it's the IWE's disengaging due to presence of vacuum.

 

 

The 97-03 f150's and Expeditions are notorious to have a loud "clunk" when turning sharp (as in pulling into a parking spot). This was due to Ford drilling a oval hole in the drivers side front control arm, rear bolt. My 04 Lightning did it bad. I was able to find a aftermarket company that made washers to compensate for the oval and make the bolt whole true. That cured my issue back then. That was a easy fix, I'm sure the drive-line in our 10 speeds isn't. I can deal with the IWE's clunking on start up. If my drive-line clunk gets louder I'm gonna be concerned like the rest of you guys.

 

I had a 2004 Ranger that did this. Drove me crazy and I never could figure it out. But it never seemed to hurt anything.

 

good idea!

 

elptxjc's statement is just wrong and I'm really wondering if he's a paid troll for Ford. The drive shaft actually jerks/ rotates backwards on engine start, then slowly comes back in the normal forward rotational direction. I have posted before that the truck will make the clunk sound even if the trucks weight is resting on the transmission, so there simply isnt any drive lash left to take up. So why does the driveshaft try to rotate backwards on engine start??

 

Truck is at dealer for the infamous start up clunk, and driveshaft jerk!

They are changing the transmission valve body, truck has been at dealer for about 7 days now.
Im pretty sure that this will NOT fix it, but Im hopeful...
I will post again if this actually fixes it, such a nice truck too, very frustrating

Seems like the tranny thinks its in reverse momentarily, than realizes its in Park. Might be a software issue, or something with the transmission linkage. IDK

BTW: I have an F-150 loaner truck with same exact motor and tranny (5.0 V8 w the 10 speed) but its a 2 wheel drive model. No clunking here, and runs/shifts great + faster bc less reciprocating parts, and XLT maybe lighter too.

Good luck everyone!

 

Good to hear your dealer is at least attempting to repair the problem. I sure do hope it is a fix. Mine has the clunk pretty bad. Even does it twice on a start up every once in a while.