Part of the John Deere Repair Manuals.
Splitting a 990 for a clutch job is no time to guess, and the John Deere 990 technical manual PDF (TM1848) puts 362 pages of factory data on your side, from the diesel engine to the three point hitch of this compact utility tractor. Electrical schematics trace every harness through the cranking and charging circuits, while hydraulic schematics map oil flow from the gear pump through the selective control valve to the rockshaft. Troubleshooting charts walk engine, power train, and steering complaints back to a cause you can test. Set MFWD spindle pinion backlash to 0.20 to 0.35 mm, and verify the steering pump against its rated 17.0 L/min (4.5 gpm) before you condemn the control unit. A dual stage clutch buried in a split tractor leaves no room for a second teardown. Print the pages the job calls for, let them take the grease on the bench, and keep the bookmarked, keyword-friendly file clean for next season.
What's Inside This Manual
| System | Pages | Key Topics |
|---|---|---|
| General Specifications | 13-15 | Metric Fastener Torque Values, Grade 7, Inch Fastener Torque Values, Gasket Sealant Application |
| O-Ring Seal Service Recommendations | 16-18 | Face Seal Fittings with Inch Stud Ends Torque, Face Seal Fittings with Metric Stud Ends Torque, O-Ring Face Seal Fittings, O-Ring Boss Fittings |
| Fuels and Lubricants | 19-22 | Diesel Fuel Specifications, Diesel Fuel Lubricity, Diesel Fuel Storage, Engine Oil, Engine Break-In Oil, Alternative Lubricants, Synthetic Lubricants, Lubricant Storage |
| Coolant Specifications | 23 | Engine Coolant, Engine Coolant Drain Interval |
| Engine - Diesel | 24-106 | Engine Specifications, Engine Troubleshooting, Engine Removal, Rocker Cover, Cylinder Head and Valves, Fuel Injection Pump |
| Electrical | 107-208 | Electrical Schematics, Wiring Harnesses, Cranking Circuit, Charging Circuit, Starting Motor, Fuel Shutoff Solenoid |
| Power Train - Gear | 209-268 | Dual Stage Clutch, Range Transmission, MFWD Driveshaft, Differential, Final Drive, PTO Shaft |
| Steering | 269-290 | Steering System Schematic, Steering Cylinder, Steering Pump, Toe-In Adjustment, Steering Control Unit |
| Hydraulics | 291-332 | Hydraulic Gear Pump, Rockshaft Operation, Selective Control Valve, Hydraulic Schematics, Rockshaft Piston |
| Brakes | 333-344 | Brake Housing, Parking Brake, Brake Pedal Adjustment, Brakes Disassembly |
| Miscellaneous | 345-362 | Three Point Hitch, Seat and Seat Support, Roll Over Protective Structure, Fuel Tank, Hood, Radiator |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Fuel nozzle internal retaining nut (nozzle overhaul) | 6.8 - 8.8 N•m (60 - 78 lb-in.) | p. 102 |
| MFWD Backlash: Spindle Pinion Gear to Outer Drive Gear | 0.20 - 0.35 mm (0.008 - 0.014 in.) | p. 210 |
| MFWD Backlash: Axle Bevel Gear to Spindle Bevel Gear | 0.20 - 0.35 mm (0.008 - 0.014 in.) | p. 210 |
| Steering hydraulic pump capacity | 17.0 L/min (4.5 gpm) | p. 271 |
| Suction Tube Elbow Cap Screws | 9 N•m (84 lb-in) | p. 289 |
| System Capacity | 26.0 L (6.9 gal) | p. 293 |
| Engine Oil Capacity | 5.3 L | p. 27 |
| Cooling System Capacity | 5.8 L | p. 27 |
| Engine Rated Speed | 2700 rpm | p. 27 |
| Cylinder Compression Pressure | 3233 kPa | p. 31 |
| Fuel Injection Nozzle Opening Pressure (4TNE) | 19600 kPa | p. 31 |
