I have had a transmission shop and a local independent car repair check my 07 V6 Camry XLE with 175k miles that doesnt shift properly into 5th gear. The engine revs up and eventually changes but it is rough. All ofther gears are fine. The car has a shifter to manually shift through the gears and it does the same thing going into 5th. When it is really cold, it hesitates and seems to "hang" a long time before finally changing. The transmission shop and the repair shop both put the car on their computer but no codes come back on the transmission. No dipstick to check fluid level or check for quality of fluid. I've had the car since 85k miles and fluid has not been changed but mechanic said we could try it, but was doubtful that would fix it. Any suggestions