I am not sure what type of hitch you have, and I am a highway dept mech. in the heart of the eastern snowbelt!! Most big plow trucks will either have a stab lock shaped like an arrowhead on the plow that slips through a rectangular hole in the mount on the truck and is retained by spring loaded locks on each side. The other common one is the gledhill style, which looks similar to the western unimount system for light trucks. Some of our older ones have what is called a houston hitch, with 2 peices of 12 inch channel verticaly running from a foot or so off the ground to the middle of the grill, and the plow carriage is slightly wider and slips over the mount on the truck. I can however offer you some insight on the IH trucks. 1, if your truck still uses a trans cooler that is one unit with the radiator, change it over to a large independent cooler in front of the radiator. I have seen lots of burned up mt400's [which is what you likely have], and MD3060's until about 2002 when IH went to a stand alone trans cooler. The cooler tubes would crack, and contaminate the trans fluid with engine coolant. 2 replace the ignition switch and plug, then buy a spare of each one, and carry them in the truck with you. 3 Check the oil feed and return line that service the turbo, I have replaced lots of these due to rust out. 4 check the oil pan, they rot out to.5 If the truck has live hydraulics, the pump probably sits out in front of the grill between the frame rails, if it does, check the u joints on the hyd pump drive shaft, as any time the harmonic balancer is turning [engine running], the joints are moving. I have seen many radiators ruined by broken u joints resulting in a whipping pto shaft. 6 check the elec connector for the wiper motor, these are known to corrode badly. 7 check the bulkhead connector where the under hood wiring harness goes into the fuse block at the fire wall engine side, these are also known to corrode. 8 check the wiper transmission for excessive play, especialy where the trans hooks to the motor arm, I have replaced more of these wiper trans than I care to remember. 9 check the cowl drain in each corner, as these plug with grit, causing the cowl where the wiper trans is to fill with water, causing fogging windows, frozen wiper linkage, and or blower motor failure. That is all that comes to mind right now for common stuff, If I think of anything else, I will post it. Do not let this list scare you, these were great trucks, they most of the time were just used in a very harsh enviroments.