Jd 650g issue

[Dustine]

Ok guys I need a bit of help. I've got a 1996 john deere 650g dozer. It is a direct drive power shift model. I've had this machine since last May and has been great. When I bought the machine the previous owner who was an elderly gent had wired the inching pedal to the side of the machine because he said at times when he depressed it, it would stick and he would have to reach down and manually unstick it. Since I've owned it if you were to come against a large imoveable object it would dump it's load off of the tracks and act just like a clutch had been depressed. Kinda like if you where on a tractor and were over loading it and pushed in the clutch the load would be taken off. This happens without the inching pedal being depressed. Since it's been cold lately the problem seems to have gotten a bit worse and the higher gears such as 2 and 3 seem to want to give at lower loads. It will still push your average cedar tree down without much issue but I'm worried that there may be a larger issue here. There has also been a clogged trans filter aler being sounded until the dozer warms up in about 15-20 mins. Any ideas what could be going on?