Poulan PRO riding lawnmower won't drive

Mine was 42" with same problem. Removed mowing deck, quite simple 5 pins and then slide out slightly to left, get on back and crawl under. To front under engine see steering mechanism exposed. Above this is a "box" , 3" tall 12" wide 12" long approximately, the engine sits on top. The drive belt runs thru this "box" . Inside there is a lever that pushes against drive belt to tighten and thus powers transmission. Mine had lots of build up of hard dry grass and was frozen. After scraping this buildup off it runs like a new mower.

I to am not a Poulan expert but do understand the basics of a hydrostatic transmission. Can't offer much to this but I will try. The belt that drives the transmission could be off a pulley and would cause the machine not to move when you push the pedal but it does not explain why the machine cannot be pushed when you release the freewheel feature. The only thing that I could think of is that something could be causing the brake not to release. Does it drag the engine down when you press the pedal down to go? If so, the brake may be locked up. You can look at it and tell if the linkage is moving when you put it on or off. If not, and your belt is turning the pulley on top of your transmission, the only external thing that I can think about is linkage. When you push the pedal, you rotate a shaft going into the hydraulic unit that makes the pump send oil to the motor that drives the wheels. Some times to see all the belts, pulleys, and linkage, you have to remove the mower deck. Usually when you do you get a good look at all the components and can figure it out. I would do that before assuming that the trannie is bad inside. Hope this helps. If not let me know and we will keep trying. Paul psmith2017@charter.net

Matt: I'm in no way an expert on the hydrostatic transmission or the Poulan, but before you pronounce the transmission dead, check the mechanical linkages. In my experience -- not a Poulan, though -- the brake/clutch pedal controls an idler pulley along the belt that runs from the engine to the transmission. When you let up on the pedal, it releases the brake and moves the idler pulley to tighten the belt, so that it turns the transmission. Sounds like that isn't happening on yours, which would explain both why the tractor won't move. But again, I'm in no way an expert on this; maybe someone with more experience has a better idea... mike