This comprehensive Technical Manual provides in-depth information for maintaining, assembling, disassembling, and servicing your John Deere 6620, Sidehill 6620, 7720, and 8820 Combines. It offers a wealth of knowledge for diagnosing, repairing, and maintaining your John Deere machinery. This manual is packed with detailed specifications, diagrams, and real-life photo illustrations, ensuring a clear understanding of each component and procedure.

The manual is organized into sections covering all key aspects of the combines, including:

**General Information:** This section includes general specifications, diagnostic and testing procedures, and tune-up and adjustment details.

**Engine Repair:** This section covers engine specifications, special tools required, cylinder head, valves, camshaft, block, liners, pistons, rods, crankshaft, main bearings, lubrication system, and cooling system.

**Fuel and Air Repair:** This section covers fuel and air system specifications, special tools, air intake system, diesel fuel system, and control linkage.

**Electrical Repair:** This section includes specifications, special tools, harness replacement, charging circuit repair, starting circuit repair, lights, instruments, and accessories.

**Power Train Repair:** This section covers power train specifications, special tools, clutch, transmission, differential, final drive, Sundstrand and Eaton hydrostatic drives, 4-wheel drive systems (Planetary Gearing and Cam Lobe), Posi-Torq ground drive, tires, and wheels.

**Steering and Brakes Repair:** This section covers steering and brakes specifications, special tools, power steering, and brakes.

**Hydraulic Repair:** This section covers hydraulic system specifications, reservoir, hydraulic pump, valves, cylinders, motors, and accumulator.

**Separator Shell Repair:** This section includes specifications, rear hood, cylinder rear cover, and separator uprights.

**Operator Station Repair:** This section covers specifications, special tools, air conditioning, air intake, heating, seating, and miscellaneous components.

**Header Repair:** This section covers header specifications, special tools, 200 and 900 series cutting platforms, 40 series corn heads, and 50, 50A series row-crop heads.

**Feeder House Repair:** This section includes specifications, special tools, feeder conveyor chain, drum, feeder house drives and reverser gear case, feeder house drives for SideHill 6620 combines, and feeder house pads, stripper, and front closure sheets for SideHill 6620 combines.

**Separator Repair:** This section covers separator specifications, special tools, cylinder, concave, beater, POSI-TORQ cylinder drive, dual-range cylinder drive, straw walkers, crankshafts, straw chopper, straw spreader, shoe augers, fan, shoe frame, tailings elevator, augers, lower auger, clean grain elevator, and grain tank loading auger.

**Grain Tank Unloading System Repair:** This section covers specifications, grain tank cross augers, vertical auger, bevel gears, horizontal auger, and gears.

**Major Drives Repair:** This section covers specifications, engine powershaft, primary countershaft, and secondary countershaft.

**Sidehill Leveling System Repair:** This section covers sidehill leveling system specifications, special tools, electrical and hydraulic components.

**Automatic Header Height Control Repair:** This section covers specifications, special tools, and repair of components.

**Engine Operation and Tests:** This section covers specifications, special tools, system operation, and tests and diagnosis.

**Fuel / Air Operation and Tests:** This section includes specifications, special tools, air intake system, diesel fuel system, and control linkages.

**Electrical Operation and Tests:** This section covers specifications, special tools, general information, diagnosis, charging circuit, starting circuit, lights, instruments, and accessory circuits.

**Power Train Operation and Tests:** This section covers specifications, special tools, clutch, transmission, final drive, hydrostatic drive tests and diagnosis, 4-wheel drive diagnosis (Planetary Gearing and Cam Lobe), and Posi-Torq ground drive diagnosis.

**Steering / Brakes Operation and Tests:** This section covers power steering and brakes.

**Hydraulic Operation and Tests:** This section covers specifications, special tools, hydraulic system operation, tests, reservoir, hydraulic pumps, valves, cylinders, motors, and accumulator.

**Operator Station Operation and Tests:** This section covers specifications, special tools, air conditioning, and heating systems.

**Sidehill Leveling System Operation and Tests:** This section covers specifications, special tools, general information, diagnosis, tests, electrical and hydraulic systems.

**Automatic Header Height Control Operation and Tests:** This section covers specifications, special tools, general information, diagnosis, tests, mechanical and electrical systems, hydraulic systems, and DIAL-A-MATIC systems (mechanical, electrical, and hydraulic).

This manual contains comprehensive information for maintaining and repairing your John Deere 6620, Sidehill 6620, 7720, and 8820 Combines, ensuring you have the resources needed to keep your equipment running smoothly.

The John Deere 6620, 7720, and 8820 Sidehill combines are powerful harvesting machines designed for efficient and precise grain harvesting in challenging terrain. These combines feature a unique sidehill design that allows them to operate effectively on slopes, minimizing the risk of tipping and ensuring consistent performance. The 6620 model, with its robust engine and generous grain tank capacity, is ideal for medium-sized farms, while the 7720 and 8820 models, boasting even more powerful engines and larger grain tanks, are better suited for large-scale operations. All three models are equipped with advanced technology features, such as automatic header height control and variable speed drive systems, to optimize harvesting efficiency and ensure top-quality grain output. They also feature a wide array of optional attachments and accessories, allowing operators to customize their combines to meet specific needs and terrain conditions.

These Sidehill combines are built to withstand the rigors of demanding harvesting conditions. Their robust construction, reinforced frames, and comprehensive safety features ensure reliable performance and operator safety. The 6620, 7720, and 8820 models offer a wide range of engine options, providing operators with the power and torque needed to handle heavy workloads. The sidehill design, combined with the advanced hydraulic systems, allows for precise control and maneuverability on uneven terrain. The operator cab offers exceptional comfort and visibility, enhancing operator control and reducing fatigue during long harvesting hours. These combines utilize a sophisticated threshing system that can efficiently separate grain from chaff, while the cleaning system ensures minimal grain loss.