I have a 2001 MTD Pro gear driven walk-behind. I've done engine/carbuerator work before, and can do all the basics myself, but I don't have the knowhow with transmissions, it seems. The clutch on this mower is operated by clamping partially down on the pistol grips - I'm sure most are familiar with this - then the shifting is done by nudging the lever (I use my knee). So here's the problem: The transmission, or maybe more specifically, the rod that changes the gears on the transmission, usually will not go beyond 1st or 2cd gear after I have run the mower for 6-8 hours (near the end of the work day). Once it is in gear, it is usually very "sticky" ie. takes a lot of oomph to shift it back from 1st into nuetral or reverse, and it simply won't go into a higher gear at the end of the day. I thought at first that it was a lack of proper lubrication - I hit both of the zerks next to the lever, and sprayed the joints with wd-40. The problem still persists, but only after I have run the mower for a good 6-8 hours. So when I'm trying to get home in the evening, then it gives me problems . Anybody have any suggestions, other than to just dish out the cash and get a new transmission?