If you're riding the clutch a lot then that most likely is it. If you're plowing at slower speeds like in a parking lot and not on the highway, maybe try putting it in 4LO and benefit from that. Sorry, I don't have a suggestion for a heavy duty cluth, haven't had to do mine yet.

1994 P'up, 22RE, K&N, LCE exhaust sys (header, cat, muffler, 2.25" pipe), 1" RB seat lift, 1" RB body lift, 1.5" rear lift via shackles, Rancho 5000's, 33" Pro Comp M/T's, 4.88's w/ Aussie lockers front & back