when I start up car cold in garage, put in reverse I get a click or rap noise one time, does not do it in forward, usually does not do it when engine is hot (no faster cold idle speed), any diagnosis tips?

CV joint?
motor mount?
strut part, like a bearing?
I30, 133000 miles, automatic

 

While putting it in gear, or while releasing the clutch pedal?
Reverse is not synchronized, and not constant mesh. When shifting into reverse the spinning gears crash when making initial contact before stopping. Normal noise for 99% of manual gearboxes.

 

Sorry I did not say, its automatic