Part of the John Deere Repair Manuals.
Pull the rocker cover on a 4640 or 4840 and you want the lash numbers in front of you before the feeler gauge comes out: 0.018 in. (0.46 mm) intake, 0.028 in. (0.71 mm) exhaust. This John Deere technical manual keeps those figures, and the procedures behind them, on the bench next to you.
Both tractors run the 6466A, a turbocharged, intercooled 466 cu. in. (7.6 L) six with mechanical injection. The 4840 is Power Shift. The 4640 came with Power Shift or Quad-Range.
Repair and Operation and Tests are split by system. A low standby pressure takes you straight to the hydraulic chapters without wading through engine work. Diagnosing Malfunctions charts list the causes and corrections for each system.
What's Inside This John Deere 4640, 4840 Manual
| System | Pages | Key Topics |
|---|---|---|
| Cover and Contents | 1-3 | Repair and Operation and Tests Section Lists |
| General | 4-77 | Specifications for the 4640 and 4840, Predelivery, Tune-Up, Lubrication, Tractor Separation |
| Engine Repair | 78-139 | Cylinder Head, Valves and Camshaft, Block, Liners, Pistons and Rods, Crankshaft, Lubrication, Cooling |
| Fuel and Air Repair | 140-193 | Air Intake and Turbocharger, Fuel System, Injection Pump and Nozzles, Speed Control Linkage |
| Electrical Repair | 194-245 | Wiring Harnesses, Charging System, Starter, Lights, Instruments, Front-Wheel Drive Electrics |
| Power Train Repair | 246-397 | Perma-Clutch, Quad-Range, Power Shift Transmission, PTO, Differential, Final Drives, Front-Wheel Drive |
| Steering and Brakes Repair | 398-429 | Power Steering, Brakes |
| Hydraulic Repair | 430-513 | Hydraulic Valves, Pumps, Rockshaft, Selective Control Valves, Breakaway Couplers |
| Front Axles and Wheels | 514-527 | Front Axle, Wheels |
| Operator Station Repair | 528-593 | Air Conditioning, Heater, Seat, Sound-Gard Body |
| Miscellaneous Options | 594-609 | Additional Lights, Trailer Brakes |
| Engine Operation and Tests | 610-623 | Engine Operation, Dynamometer Test, Engine Diagnosis |
| Fuel and Air Operation and Tests | 624-661 | Air Intake, Turbocharger, Fuel System and Linkage Operation, Tests and Diagnosing Malfunctions |
| Electrical Diagrams and Diagnosis | 662-797 | Wiring Diagrams, Step-By-Step Electrical Diagnosis |
| Electrical Circuit Operation and Tests | 798-843 | Charging, Starting, Lights, Instruments, Front-Wheel Drive and Electrical Console Circuits |
| Quad-Range Operation and Tests | 844-871 | Quad-Range Transmission Operation, Pressure Tests, Diagnosing Malfunctions |
| Power Shift Operation and Tests | 872-921 | Power Shift Operation, Oil Flow by Gear, Pressure Tests and Diagnosis |
| Differential and Front-Wheel Drive Operation and Tests | 922-943 | Differential, Final Drives, Front-Wheel Drive |
| Steering and Brakes Operation and Tests | 944-971 | Power Steering and Brakes Operation and Tests |
| Hydraulic System Operation and Tests | 972-1047 | Hydraulic System Operation, System Tests, Diagnosing Malfunctions |
| Hydraulic Component Operation and Tests | 1048-1103 | Valves, Pumps, Rockshaft, Selective Control Valves, Flows and Pressures |
| Operator Station Operation and Tests | 1104-1151 | Air Conditioning Operation, Tests and Diagnosis, Heater, Seat |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Engine displacement (6466A, 6-cylinder, turbocharged, intercooled) | 466 cu. in. (7.6 L) | p. 4 |
| Bore and stroke | 4.56 x 4.75 in. (116 x 121 mm) | p. 4 |
| Compression ratio | 14.9 to 1 | p. 4 |
| Factory observed PTO horsepower, 4640 / 4840 | 155 hp (116 kW) / 180 hp (134 kW) | p. 4 |
| Valve clearance, intake / exhaust | 0.018 in. (0.46 mm) / 0.028 in. (0.71 mm) | p. 4 |
| Slow idle / fast idle | 780-820 rpm / 2325-2425 rpm | p. 142 |
| Cylinder head cap screws, initial and second torque | 105 ft-lbs (142 Nm) initial, then 117 to 143 ft-lbs (158 to 193 Nm) | p. 97 |
| Cylinder head cap screws, retighten after 1/2 hour at 2100 rpm | 135 to 165 ft-lbs (183 to 224 N-m) | p. 98 |
| Main bearing caps torque | 150 ft-lbs (203 N-m) | p. 80 |
| Connecting rod cap screws torque | 55 ft-lbs (75 N-m), then an additional 1/4 turn (90 degrees) | p. 80 |
| Engine oil pressure at 1900 rpm | 40 to 50 psi (2.75 to 3.75 bar) | p. 81 |
| Thermostat opening temperature | 160 to 180°F (71 to 82°C) | p. 82 |
| Intake manifold boost at 2200 rpm full load, 4640 / 4840 | 16-19 psi (1.1-1.3 bar) / 18-21 psi (1.2-1.4 bar) | p. 141 |
| Injection nozzle opening pressure, new | 4050 psi (279 bar) | p. 142 |
| Hydraulic standby pressure, 3.0 / 4.0 cu. in. pump | 2200 to 2300 psi (151.7 to 158.6 bar) / 2250 to 2300 psi (154.7 to 158.6 bar) | p. 973 |
| Main hydraulic pump output at 2000 psi, 3 / 4 cu. in. pump | 23 gpm (87 L/min) / 26.5 gpm (100 L/min) | p. 973 |
| Oil regulating valve, Power Shift / Quad-Range | 175 to 185 psi (12.1 to 12.8 bar) / 155 to 165 psi (10.7 to 11.4 bar) | p. 973 |
| Differential lock pressure | 435-485 psi (30.0-33.4 bar) | p. 845 |
| Transmission-hydraulic oil, Quad-Range (4640), drain and refill | 22.5 U.S. gal. (85.2 L) | p. 5 |
| PTO speed and shaft size | 1000 rpm at 2200 engine rpm, 1-3/4 in. (45 mm) | p. 5 |
John Deere 4640, 4840 Common Problems This Manual Covers
Engine starts hard or will not start
Start with the fuel. A clogged fuel filter starves the injection pump, so replace the filter. If there is water in the fuel, drain it out of the system and install new filters. The Fuel and Air Operation and Tests section carries the full Diagnosing Malfunctions chart for the fuel system.
Manual Section: Fuel and Air Operation and Tests p. 641Engine emits excessive black smoke
Check the air cleaner first. A restricted element chokes the engine, so clean or replace the elements. If the smoke is still there, the turbocharger may be defective and needs repair. A boost check helps confirm it: 16-19 psi (1.1-1.3 bar) on the 4640 and 18-21 psi (1.2-1.4 bar) on the 4840, at 2200 rpm full load.
Manual Section: Fuel and Air Operation and Tests p. 629Quad-Range clutch slips (4640)
Rule out the operator first. Riding the clutch pedal will slip it every time. Next, the clutch valve may not be engaging completely, so run the clutch pressure test. If pressure is good, the engaging levers are probably out of adjustment, so adjust the clutch pack using the Perma-Clutch procedure.
Manual Section: Quad-Range Operation and Tests p. 864Differential lock does not work
Put a gauge on it. Lock pressure should be 435-485 psi (30.0-33.4 bar). If the lock valve pressure setting is low, add shims to bring it up. If pressure will not hold, look for leaking oil seals or a leaking gasket and repair them.
Manual Section: Differential and Front-Wheel Drive Operation and Tests p. 925Frequently Asked Questions
Does this manual cover my John Deere 4640 or 4840 tractor?
Yes. It is the John Deere technical manual for both the 4640 and the 4840, and both run the 6466A six-cylinder turbocharged, intercooled diesel at 466 cu. in. (7.6 L). The 4840 has the Power Shift transmission. The 4640 came with Power Shift or Quad-Range, and the Quad-Range and front-wheel drive chapters are marked 4640 only. p. 1
What are the John Deere 4640 and 4840 valve clearances and idle speeds?
Set intake valves at 0.018 in. (0.46 mm) and exhaust at 0.028 in. (0.71 mm). Slow idle is 780-820 rpm and fast idle is 2325-2425 rpm. Rated engine speed is 2200 rpm. p. 4
What are the John Deere 4640 and 4840 cylinder head, main bearing and connecting rod torque values?
Head cap screws go to 105 ft-lbs (142 Nm) first, then 117 to 143 ft-lbs (158 to 193 Nm). After the engine runs 1/2 hour at 2100 rpm, retighten them to 135 to 165 ft-lbs (183 to 224 N-m). Main bearing caps take 150 ft-lbs (203 N-m). Rod cap screws take 55 ft-lbs (75 N-m), then an additional 1/4 turn (90 degrees). p. 97
What are the hydraulic system and transmission pressures on the 4640 and 4840?
Hydraulic standby pressure is 2200 to 2300 psi (151.7 to 158.6 bar) with the 3.0 cu. in. pump and 2250 to 2300 psi (154.7 to 158.6 bar) with the 4.0 cu. in. pump. The oil regulating valve is set at 175 to 185 psi (12.1 to 12.8 bar) on Power Shift and 155 to 165 psi (10.7 to 11.4 bar) on the 4640 Quad-Range. Differential lock pressure is 435-485 psi (30.0-33.4 bar). p. 973
What is inside this manual: repair procedures, wiring diagrams, hydraulic schematics, diagnosis?
All of that. Repair sections cover the engine, fuel and air, electrical, Perma-Clutch, Quad-Range and Power Shift transmissions, PTO, differential, final drives, front-wheel drive, steering, brakes, hydraulics and the Sound-Gard body. The Operation and Tests sections add wiring diagrams for tractors with and without the Sound-Gard body, color hydraulic schematics for Quad-Range and Power Shift tractors, pressure tests and Diagnosing Malfunctions charts. p. 3
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