My 3 yr old 1046 seems a little sluggish in tight turns, with its speed slowing and a whine from the tranny. I have been reading up on my model and it appears I have the transaxle with drain and fill plugs. Now my question is how difficult it is to get to the fill plug? It is worth removing the unit or removing the fender? any tips or thoughts from the pros out there? Draining it is the easy job... Also, is it OK to use 20w-50 synthetic in it? Thanks!