walk behind will not go in self propelled

[dwint]

I bought a used troy bilt 12av839n711 and the guy said it needed a belt.bought the right belt and it will not go forward.when I lift the mower while running I cant hold the rear wheels.when I put it down it wants to move but don't.if I try to hold the rear wheels I cant stop them.when I put the mower down it don't go.it has the spur gears on the right side and new rear wheels with the gears.the cable is also all the way out.i don't understand what could be causing this

 

[possum]

Sounds like your gear box has had it . They are 100 bucks online.

 

[bjl8691]

Dont those mtd branded products have plastic internals on those gear boxes?

 

[dwint]

yes they are plastic I took the cover off to make sure things were working right.i turned the pulley by hand to make sure the gears were turning

 

[dwint]

if the trans was bad I would be able to stop the wheels correct?