Outdoor Power Equipment and Small Engines - How to change fluid in sealed hydrostatic tranny

I have a White (by MTD) with a hydrostatic tranny. It has a sealed hydrostatic unit. The belts are new and tight and the fan is new. We have had the mower for over 10 years and have used the snot out of it. It has a new engine and now a used replacement deck. I am sure the hydro unit is low and very dirty. It whines more than it used to especially when cold. The mower has been used and abused 2 times over. How do you drain and refill a sealed system? Also what type of oil do you put back in it and can you use synthetic?

If it's truly a sealed unit, you pretty much can't drain and refill it. Also, if it's sealed and not leaking, it's probably fairly clean and full. Some have a spot on top where you can add fluid, but usually no way of checking the level. It may have a removable vent where you could add a small amount.

The original fluid got in there somehow, so carefully and thoroughly clean the rear axle and look for threaded plugs. You may have to remove the rear axle to tilt it so all the fluid inside can drain out. I'm not familiar with your tractor, so I don't know what or how much to put back in. But remember that dirt and grit are the ENEMY of a functioning hydro unit. Any dirt introduced in the system can cause damage, so if you decide to do this, keep everything CLEAN.