Thud from rear? slowly coming to a stop

[Smittyjf]

My 19 ST has always had some transmission oddities since I purchased it new (May 19) It would Clunk loudly going into drive from park and switching from reverse to drive. It would slip a little going from reverse to drive and moving forward. It also recently developed some strange bumps/thumps while moving in NY bumper to bumper traffic. just inching along not pressing the gas pedal. I took it in and they did the PCM update and said It was fixed.Since then I have not been in bumper to bumper traffic, but noticed this thump when slowly coming to a red light or a stop sign right before you stop. I sounds like something shifting in the cargo area like a ball rolling from the tailgate to the back seat. Not extremely loud but it sounds like something disengaging. I emptied everything from the cargo/under cargo area, the consul and nothing under the seats. I can make it do it 10/10 times so it's something mechanical. I'm dropping it off next week so they can have it for 5 days while I'm gone away. 

 

Smitty

[Perblue]

There is a tsb for the straps for the fuel tank. Something about them being too loose and replacing them with different ones.

 

MC-10153937-9999.pdf (nhtsa.gov)

 

Could also be something to do with the brakes but I'm just taking a shot in the dark.

[Fingernip]

Hopefully its not the same problem I'm having. I believe the viscus coupler at the RDU is failing or the RDU itself. During driveshaft engagement and disengagement it had a grumble/grind and sometimes a thud. Its most noticeable during light acceleration around a turn and when coming to a stop. Slowly gotten worse and is now to the point where I'm feeling drag from the rear end. Dealership attempted a TSB reflash and it just got worse. Also have a leaking oil pan and waiting a updated oil pan replacement. Oil leak got so bad its burning on the exhaust. 

[WWWPerfA_ZN0W]

rumble/grind is never good - almost always a failing differential involved. a thud CAN be due to the programming needing to be updated.

[enigma-2]

AWD or FWD?

[rkloeckner]

On 7/9/2021 at 5:17 PM, Smittyjf said:

My 19 ST has always had some transmission oddities since I purchased it new (May 19) It would Clunk loudly going into drive from park and switching from reverse to drive. It would slip a little going from reverse to drive and moving forward. It also recently developed some strange bumps/thumps while moving in NY bumper to bumper traffic. just inching along not pressing the gas pedal. I took it in and they did the PCM update and said It was fixed.Since then I have not been in bumper to bumper traffic, but noticed this thump when slowly coming to a red light or a stop sign right before you stop. I sounds like something shifting in the cargo area like a ball rolling from the tailgate to the back seat. Not extremely loud but it sounds like something disengaging. I emptied everything from the cargo/under cargo area, the consul and nothing under the seats. I can make it do it 10/10 times so it's something mechanical. I'm dropping it off next week so they can have it for 5 days while I'm gone away. 

 

Smitty

 

Smitty, what did it end up being? 

[kruzr1]

My 19 ST use to make this thud noise at around 13 mph. I never took it in because I figured if it was something serious I would get a warning. The dealer probably wouldn't acknowledge it anyway and it's difficult to even get an appointment.  Then recently I noticed the sound was gone. About the only thing that has changed is the weather, colder.