OEM parts categories for 1991 Gmc G2500: Body Mounting, Air Conditioning, Audio/Entertainment (A/C & Heater Control Assembly, A/C & Heater Module Assembly, A/C & Heater Module Assembly/Rear Air, A/C Compressor Assembly, A/C Compressor Mounting, A/C Control System/Vacuum & Electrical, A/C Refrigeration System, A/C System/Rear, Air Distribution System/Instrument Panel, Air Distribution System/Plenum, Air Inlet, Audio System & Antenna, Cluster Assembly/Instrument Panel) | Brakes (Brake Booster/Vacuum, Brake Caliper/Front, Brake Lines/Rear Crossover Pipe, Brake Master Cylinder, Brake System, Parking Brake System, Wheel Cylinder/Drum Brake Rear Wheel) | Brakes, Rear Axle, Propeller Shaft, Wheels, Tires (Axle Assembly/Rear, Brake Assembly/Rear Drum, Differential/Locking, Prop Shaft, Prop Shaft And Mounting, Vibration Dampener/Drive Line, Wheels & Wheel Covers) | Cab And Body Structure, Mirrors, Doors, Trim, Seat Belts, Wipers (Door Hardware & Trim, Door Hardware/Rear, Door Hardware/Side Rear, Door Hardware/Side Rear Sliding, Door Hardware/Side Rear Swingout, Door Trim/Rear, Door Trim/Side Rear Swing Out, Door Trim/Side Rear/Sliding Door, Engine Cover & Related Parts, Engine Cover & Related Parts/Sheet Metal, Floor Covering & Related Parts Flooring & Step Wells, Floor Covering & Sill Plates, Instrument Panel & Related Parts, Insulators/Dash Panel, Insulators/Floor, Insulators/Floor & Rear Wheel Housing, Lamp/Dome & Reading, Mirror/Inside Rear View & Sunshades, Mirror/Outside Rear View, Power Window & Door Lock System, Rear Seat/1st & 2nd Bench, Seat Belts & Related Parts, Seat/Bucket, Seat/Travel Bed, Sheet Metal/Body Side, Sheet Metal/Roof, Trim/Interior Side, Trim/Interior-Roof, Vent Window/Front Door, Windows/Glass, Windshield & Windows/Body Side, Wiper System/Windshield) | Cooling System, Grille, Oil System (Engine Oil Cooler, Engine Oil Cooler And Lines, Engine Oil Pressure & Temperature Switches, Grille/Radiator, Pulleys & Belts, Pulleys & Belts/Accessory Drive, Radiator Assembly, Radiator Mounting & Related Parts) | Engine (Engine & Transmission Mounting, Engine Assembly & Partial Engine) | Frames, Springs, Shocks, Bumpers, Fascias (Bumper/Rear, Spare Wheel Carrier, Suspension/Rear, Trailer Hitch) | Front Axle, Front Suspension, Steering (Steering Column/Tilt Wheel, Steering Gear Assembly, Steering Pump Assembly, Steering Pump Mounting & Lines, Steering System & Related Parts, Steering Wheel & Horn Parts, Steering/Brake Pump Mounting & Lines, Suspension/Front) | Front End Sheet Metal, Heater (Heater & Defroster System & Blower Details, Heater Assembly Rear Auxiliary, Heater Control Assembly, Heater System/Rear, Hoses & Pipes/Heater, Jack & Tool Stowage, Sheet Metal/Front End) | Fuel System, Exhaust, Emission System (A.I.R. Control Valve & Related Parts, A.I.R. Pump & Related Parts, Accelerator Control, Accelerator Pedal & Rod, Air Intake System, Cruise Control, E.C.M. Module & Wiring Harness, E.G.R. Valve & Related Parts, E.G.R. Valve & Vent Tubes, Emission Controls Actuator, Valve & Harness, Exhaust System, Fuel Filter, Fuel Injection System, Fuel Supply System, Fuel Tank & Supply, Heat Shields/Exhaust, Injection Pump/Fuel, T.B.I. & Related Parts, Throttle Body & Sensors, Throttle Body Injection, Vacuum Pump & Related Parts, Vapor Canister & Related Parts) | Rear Body Structure, Moldings & Trim, Cargo Stowage (Decals & Nameplates/Endgate, Moldings/Body) | Starter, Generator, Ignition, Electrical, Lamps (Distributor/Ignition, Generator Assembly, Generator Mounting, Headlamps-Single, Headlamps/Dual, Lamps/Rear, Spark Plug Wiring, Starter Motor) | Transmission - Automatic (Automatic Transmission Auxiliary Accumulator Valve, Automatic Transmission Case & Related Parts, Automatic Transmission Clutch Gears, Automatic Transmission Control Valve, Automatic Transmission Oil Cooler Pipes, Automatic Transmission Oil Pump, Automatic Transmission Overrun Clutch, Automatic Transmission Parking Lock Linkage, Automatic Transmission Valve Body, Shift Control)