Bush Hog ATH600 Gearbox Leak

MattB2710 · Feb 9, 2004

Was out in my shed this morning, and found the gearbox on my Bush Hog ATH600 Finishing Mower has been leaking oil.
The mower was purchased in 1999 and has less than 100 hours of use. Shed is unheated. What attacted me to the leak was a heavy grease/oil smell. Oil, light brown in color, is leaking on the upper deck of the mower and is running off the back of the deck, there is no oil under the mower deck. Warranty was only 1 year. Have called Bush Hog for parts diagram. I think an upper seal maybe leaking.
Anyone else have similar problems?
Any ideas on repair suggestions?
Thanks,
MattC

L3710GV · Feb 10, 2004

I don't know if finish mower gear box is the same but on a field mower gear box that leaks oil the fix is to check bearing preload and replace seal-

When the shaft has to much side-side play it takes out the seal which causes gear box to leak oil-- and if not caught in time blows up gearbox

greg_g · Feb 10, 2004

Mine leaked around the coarse threads of the fill plug, but it occured only when the transmssion was spinning. I fixed it with teflon tapes and an extra turn. If yours did this just sitting there in a cold shed, you might have water in the transmission. Gear oil floats, and water expands when it turns to ice. The expansion could have forced oil past the fill plug threads, then ran down to pool at the base of the transmission.

//greg//

Bird · Feb 10, 2004

Matt, where is the leak? Input shaft, vent, filler plug?

MattB2710 · Feb 10, 2004

Bird,
It appears to have leaked out the output shaft, or the bottom of the gearbox. I opened up the filler/inspection cap and the gearbox case appears to be empty/dry.
What a stinky mess to clean up.