I have a Lawnboy model #10515, Serial #3913965. I bought it new in '93 (I think) It's been a great mower for almost 30 years. Last weekend the self propelled function died. 
I have been lawn mower shopping, but I'm not ready to buy something thats made mostly of plastic, and has little chance of lasting 5 years. The motor on this mower runs fine. Motor runs, belt turns, pulley on transmission spins, mower does not move. In any of the 3 gears. I figured I couldn't break it any worse, so I split the transmission. The pinion gear, bevel gear, and all gears look good. No metal pieces or shavings in the gear box. I can spin the final drive gears, and I can turn the axle, niether has any effect on the other. Maybe if I power washed the grease out of the tranny, I could see more. Can someone tell me what engages the final drive gears to the axle? Does this sound fixable? Thanks Greg
I have been lawn mower shopping, but I'm not ready to buy something thats made mostly of plastic, and has little chance of lasting 5 years. The motor on this mower runs fine. Motor runs, belt turns, pulley on transmission spins, mower does not move. In any of the 3 gears. I figured I couldn't break it any worse, so I split the transmission. The pinion gear, bevel gear, and all gears look good. No metal pieces or shavings in the gear box. I can spin the final drive gears, and I can turn the axle, niether has any effect on the other. Maybe if I power washed the grease out of the tranny, I could see more. Can someone tell me what engages the final drive gears to the axle? Does this sound fixable? Thanks Greg