Hello,
I have a 997.1S X51 with rebuilt engine (8000 miles on it). Brand new clutch too, manual transmission with short shift. There’s a creaking sound coming from the rear when I lift my foot from the throttle (to change gears), noticeable only above 3k rpms. Sound doesnt go away when engine is warm.
Only happens when letting go of throttle above 3k. Nothing to do with the clutch.

will take it to my dealer, but anything you guys think?

Thanks! (Pic below for science)

 

First thing I'd check is the motor/transmission mounts.

 

What Kitc said. Other thing I'd check is sway bar bushings, especially if the temperature just changed where you are. The lift off changes the load on the rear suspension and the sway bar rotting in its mounts can cause a squeak or creak if they're dry.

 

Thanks both! Weather indeed became abruptly colder here.

With no tools/time/knowledge, what can I do myself now? WD40 on the motor mounts?

Planning to take it to the dealer when the snow melts.

 

Nothing really. Sway bar would need to be removed and the bushings regreased or replaced. If the motor mounts or trans mount is creaking, it's internal to the motor mount and won't really change with external lubrication, the exception being if the mount to the carrier is actually loose, in which case torquing it back to the proper tightness should also eliminate the creaking. Really, you'll likely just have to live with the sound until you take it in and find the source and cause.