If I'm not mistaken, the book calls for 1 shot daily. I definitely wouldn't grease as much as you are. You could be pushing grease past the seals and it is getting up on the belt. But you should be able to see that if it's happening. I was thinking torque spring until you said you just changed it out. I know they changed the angle on the torque hub on the later 2388's because they decided the original angle was too steep. I have seen the pins that fit between the pulley halves get grooves in them, and while they may move fine when not in a bind, once they get a load on them they may not be able to move. Also, are you sure you've adjusted the driven pulley so that the distance between the two pulleys is correctIJ If they're too close, the belt won't have the proper tension on it and will slip. That's about all I can think of. Good luck!