My neighbor took his john deare into have the drive belt replaced and spent 500 and still won't go up hills the rear end is making a huming noise so how can u check the fluid on it if its sealed

Hi,
It is either the pump or the motor or both that are down on tolerances. It is likely that Tuff-Torq has updated versions of them. If you pry out that round plug at the high part of the transaxle, the oil level should 1 3/8" below it. It uses high quality 10W30 to add.
There are videos on YouTube about replacing the pump and motor assemblies, both are generally done at the same time. There are also a pair about upgrading the machine to a K66 transaxle.
Peace,
Clarke