STX38 Wont move forward

[Lawnmower collector]

I have a Stx38 with transmission problems, it won't move forward in any gear it just pops and makes a rapid clunking sound, everyonce in a while it will catch and inch forward. It's acting like something it stripped or slipping but it will move in reverse fine. I removed the transmission from the mower and took it apart and the only thing I can see is one of the bevel gears on the axle has stripped the teeth halfway off the gear. Would that be the problem? When shifting through the gears and turning the gear that the input shaft turns the large differential gear moves in all gears.

 

[tom3]

That would sure do it I'd think. Some of the newer mowers have pressed/powdered metal gears in the final drive, bad application in my book but I guess it's cheap and lasts a while even so. I'd try to find and replace both side gears.

 

[Lawnmower collector]

Okay, looking at them again they aren't as bad as I thought they were after cleaning out the old bentonite,but they could still be the problem. The axle shafts also had some up and down slop and the input shaft bearings are toast.