Clunk When On/Off Throttle Highway Speeds?

[Jerome10]

I admit I never know when things should go in the general discussion or the issues, tsb forum....

With that said, after doing some searching on the forum I haven't come across any existing threads. Perhaps just not searching the right terms.

But my truck seems to somewhat frequently have a clunk or thud on the highway if I release the throttle then shortly after reapply throttle, even if gently reapplying the gas. Trying to pay attention and it seems to 1) be in 10th gear (I've maybe noticed it a few times in other gears but I'm almost always in 10th when it occurs) 2) somewhere within a couple MPH of 60mph 3) often (i think) more common if on a slight downhill slope, and 4) you need a few seconds of off-throttle before re-applying the gas (so a quick off throttle then on-throttle usually doesn't do it).

It isn't a downshift. Truck clearly stays in 10th the entire time. To me it feels more like gear teeth with too much slop or something. Like you let off the gas, the 2 gear sets stop being locked together, and then as soon as the gas is re applied the teeth kinda bang back into each other. Not a grinding noise at all. Clunk or thud sound.

Never had a single car or crossover do anything like this. Wondering if an issue at all or something common in trucks or what. Realize this could be transmission, driveshaft, differential? If I had to guess I'd say it is not the differential as it feels like it occurs more under my seat or slightly forward of the driver's seat.

Its annoying and feels like there is a problem but I'm curious if this is "normal" like so many other odd things these trucks often do.

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[HammaMan]

Driveline backlash being felt due to regen functionality. Haven't checked what ford did to revise this with PCM updates, but I suspect it may be unlocking or slipping the torque converter to hide it going back and forth from regen to accel and vice versa.

 

[Bulldog]

I just had this happen to me. We were on the interstate and had been cruising along for about an hour. Had to slow down for a crash and as we were coming to a stop here was a loud clunk that shuddered through the truck. Truck was in 4A as there was ice on the road. I also happen a few times in two-wheel drive in my 2021. Both 5.0 with ten speed.

 

[Jerome10]

Driveline backlash being felt due to regen functionality. Haven't checked what ford did to revise this with PCM updates, but I suspect it may be unlocking or slipping the torque converter to hide it going back and forth from regen to accel and vice versa.

oh interesting. So this could be rather specific to power boosts?

Driveline backlash… would this then also occur on all pickups? Why wouldn’t I have experienced it in something like a Grand Cherokee (rear drive biased SUV, but not on a truck platform)?

 

[Jerome10]

I just had this happen to me. We were on the interstate and had been cruising along for about an hour. Had to slow down for a crash and as we were coming to a stop here was a loud clunk that shuddered through the truck. Truck was in 4A as there was ice on the road. I also happen a few times in two-wheel drive in my 2021. Both 5.0 with ten speed.

Welp maybe not powerboost specific.

Sounds like this might be one of those things these trucks do? Is there any solution?

I will mention next time at dealer as well.

 

[Jerome10]

Still having this happen, almost always at 60mph or so.

I’ve read some about people having to grease the slip yoke. But the symptom seems to be more 1 single clunk when starting from a dead stop. Not coasting a few seconds then hitting the throttle again.

Anyone here possibly had this issue and tried greasing the slip yoke?

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