Q: Transmission hot idle engine what is the problem

Transmission fluid and condition can cause the transmission temperature to rise. The transmission relies on the fluid not only for hydraulic pressure to move the vehicle and change gears, but relies on it for cooling as well. Low fluid level reduces cooling efficiency as does the fluid condition. If the fluid is old and dark, it does not absorb and shed head heat very well. A transmission fluid service may correct this if the fluid condition is poor. There can also be an electronic fault with something like the transmission temperature sensor. A certified technician can inspect the transmission fluid as well as scan the system for faults and sensor values. They can determine the exact cause and correct the problem. Have it inspected as soon as possible to prevent any damage to the transmission. Overheating the transmission can damage it quickly.