recently got a reasonable seal on a a/c C model with a 72" woods mower, like any older machine it needs some attention, one thing i noticed is a noise in neutal with the clutch released, its probapby there when driving too, but cant hear it over the engine. im thinking its either a input shaft or countershaft bearing. i read somewhere that the trans oil is 20wt motor oil, im wondering if it would be better (and buy me some time) to run a 80/90 in the trans like the final drives have. im not going to be using the hydraulic lift, just the pto for the mower, good/bad idea? i realize at some point the bearing will go regardless, but if a 80/90 would be better and let it make it a last a little longer-why not?