2008 White LT5000 with 50" deck (MTD) with hydrostatic transmission. I had a main crank oil seal leak, so I replaced it and added new engine oil. I fired it up and nothing was leaking. This was the first time running since last season. A few days later, when I press the throttle pedal, it starts to creep but as I press it further, the pedal resistance disappears and the tractor stops moving. It will return if I back off the throttle pedal all the way, and then lightly press it, but if the problem persists if I keep pressing the pedal forward. This makes it very annoying to drive, and almost impossible to climb a slight hill. If the land is flat enough, and you maintain a light pedal press, the tractor will slowly get up to top speed, but this is the only way it will go fast. I'm not sure if maybe oil leaked onto the drive belt or if its a transmission issue, or if it simply needs adjustment. What do you guys think?