I got my Mark LT serviced for the thump/clunk problem and they said that it wasnt the driveshaft yoke and they reseted the computer for the transmission shifts and that didnt fix the problem!

so what to do now?

 

I have 90K on a 2004 F150 and I have had similar problems with my truck.
Once it was the transmission clutch and recently they found play in the driveshaft spline. Both were under warranty.
The clutch clunk was softer and had a shudder along with the noise.
The driveshaft spline was harsher but came and went at times.

Sometimes service at the dealership is all about the tech doing the work more than the problem. They always fix my truck the 1st time, everytime.
At another dealership they always needed 2 or three tries to get it right.
Since 2001 I take my trucks to the same place...same tech.