Well I must admit I never touched mine after mowing but a sealed gearbox that small that is air cooled and spinning as fast as it does will be pretty hot. Keep this in mind as well. Your hydraulic fluid that powers your HST and tractor hydraulics will run about 100 degrees above ambient temperature. So just feel one of your quick connects after running the tractor for about an hour. I'm sure you MMM is just fine, but you could always check the level to give you piece of mind.
What your sayings is true, i did check fuild level
and it seemed fine. i did check it hot and a small amount
squirted out do to pressure build up . thanks for your insight
You might try changing the gear oil to a synthetic and see if that improves it at all. At worst you've changed the fluid to one which has a higher temp threshold. I run Mobil 1 synthetic in my mower deck gearbox and the front axle on my B2400.