I wonder why Mack got out of the offroad truck business. I ran a small rock quarry back in 1980, and we had a little Mack haul truck we used as a backup. It was about a 25 ton truck I would guess. That old Mack was a tough little rig. I don't ever remember it being down for anything, and it got used quite a bit, even though it was a back up unit. It had a Mack engine in it, but I don't know what model or size the engine was. A couple of the drivers liked it better than our R22 and R25 Euclids. Said it was a lot quieter.
Jeff