It does have a ball diff.
Took it down and all was fine.
The pads and plates look good but i put new ones and scuffed the plates.
Pulled the motor and it was fine also. (tekin 17.5bl)
I noticed that it slips on the track only at the 15+min mark of batt. If I
hold off the ground it ballons the tires easy and seems fine.
That would tell me diff, I would think but It checked ok...lol
Anyways, I rebuilt diff. and adjusted everything to spec. and will see what happens today. I'll let you know