I have my truck just over a year now and ever since I bought it, it seems to have a hard shift from 3'rd to 4'th when I am not heavy on the accererator pedel. It makes a somewhat noticable loud noise, and the speed is right about 45 MPH. Any thoughts on this? If I am heavier on the fuel pedal, it does not shift until a higher speed (55 MPH) and does not make the clunk noise. It is almost as if I am lugging it with an automatic transmission in fourth gear. Thanks

 

Mine does the same thing. The torque converter is locking up and causing the turbo to bark a little. Very common in the 3 Gen's with the 48RE's.

 

Mine barks everytime on light to medium throttle lock ups. I quit caring...