Replace the connector on the truck and the battery. You can't go wrong there, even if it does not fix the problem. By replace, I mean the tips and housing. Don't just replace the housing. Resistance in the connection between the tips and the cable means HEAT.

have your battery company replace the cables, if ONLY 1 cable is getting hot. have your battery checked out for "voltage drop under load".
lower voltage = higher amperage = (same wattage to do the work) but more heat. since electric power is a circuit, the flow on both cables is equal, if only 1 is getting hot, then that one (most likely) has broken down inside the insulation.
also check the connector to the battery (all 3 halves, truck, battery and charger) charger half may have a weak spring or cracked case causing poor connection at the charger, causing poor connection on the truck and battery too.