I have a G110 ,hydrostat drive, machine has about 439 hours on it , it does not have the ground speed it used to and backing up it moves slower, is this the belt ? Are there any adjustments that can be made

Hi,
You have quite a few hours in that machine. First see if there is a visible sign of leaks(dirt buildup) that are obvious. The unit is listed as not serviceable, but if it leaks there is a way to add oil, 10W30.
It could be the belt or one of the idlers. There is a diagram of the belt routing at the site in my signature.
Peace,
Clarke