Feeling a bump in 3rd gear with a "donking" noise

[bluecheese]

2021 1500 with etorque

When driving in traffic, when I let off the gas and let the truck cruise, it feels like the truck wants to downshift. But if I put my foot on the gas, occasionally I'll feel a slight bump and hear what I can only describe as a "donk." But it doesn't shift up or down according to the gauge cluster.

I'm pretty sure it only happens when I'm in 3rd gear.

I searched and I've seen a couple of other threads with people with the etorque having similar issues (just in different gears.) But with no definitive answer.

Any ideas? I'm dreading having to take the truck to the dealership service department.

 

[bluecheese]

Noticed this morning, that's not only doing this in 3rd gear. Feeling/Hearing the same thing in 4th and 5th gear.

 

[bluecheese]

Anyone?

 

[bluecheese]

I know I'm talking to myself here, but I thought it may be the U joints. I just checked them, and they look brand new. No play in them or the drive shaft.

 

[bluecheese]

I’ve had two different mechanics check out then joints, and they confirmed that they were fine.

Googling the issue, it turns out that people experiencing the same have greased the drive shaft slip yoke, and the issue disappeared.

So I got some red tacky grease, removed the back half of the shaft, and greased the F outta the splines.

I’ve only driven it a little since doing this, but the clunk seems to have disappeared.



I’m posting this in case someone having a similar issue stumbles across this thread.