Welcome to the forum riden!
I have no expertise on them other than what I have read from various forums. My LT150 uses a sealed unit that I have had no problems with so far (knocking on wood
). If it is possible on that unit to drain and refill the unit I would try that first. There also would probably be a filter in it that could be plugged up. I suppose you could put something like kerosene in there to flush it out before refilling with oil. But do not know if there would be any parts that could be damaged by doing that. Do you know what type of oil it requires to refill it. Mine uses motor oil but some require other types of oil. Before doing all of that, if you have not checked already, make sure your drive belt or pulley is not slipping and the bypass lever (assuming you have one, mine is a rod sticking out the back by the trailer hitch) is fully in the engaged position.