I've noticed that many times, when slowing down from higher speeds (45MPH+) that as I'm slowing down, when the transmission is downshifting, either the transmission or driveshaft makes a clunking noise as it's downshift into one of the lower gears. It doesn't happen so much at lower speeds (20-40MPH), and happens whether I'm stopping quickly or even just coasting to a stop. The truck drives fine, other than this issue. I'm more concerned because the sound sounds like a metal-on-metal clunk when it happens.
Upshifts during acceleration is fine (with the occasional hiccup, where it may overrev slightly and then quickly shift into the next gear--but this happens rarely--maybe less than once a month, and usually when its colder out or when the truck is not completely warmed up).
But the audible clunk happens quite often, cold or warm weather.
The truck has the 5.3L Vortec (its a 2013) with the 6 speed automatic, and is 4WD with the Automatic transfer case (if that matters any). I also have the heavy-duty rear locking differential as well, so I don't know if maybe the noise is related to that disengaging/engaging. No modifications have been made to the engine or transmission.
Upshifts during acceleration is fine (with the occasional hiccup, where it may overrev slightly and then quickly shift into the next gear--but this happens rarely--maybe less than once a month, and usually when its colder out or when the truck is not completely warmed up).
But the audible clunk happens quite often, cold or warm weather.
The truck has the 5.3L Vortec (its a 2013) with the 6 speed automatic, and is 4WD with the Automatic transfer case (if that matters any). I also have the heavy-duty rear locking differential as well, so I don't know if maybe the noise is related to that disengaging/engaging. No modifications have been made to the engine or transmission.
