Part of the John Deere Repair Manuals.
This is the factory John Deere technical manual TM-1229 covering both the 644C wheel loader and the 646C landfill compactor, about 1,378 pages of teardown, spec and test procedure. It runs from wheels, axles and the power shift transmission through a full overhaul of the 466 cu. in. turbocharged diesel, torque converter, steering, brakes, electrics and the closed-centre main hydraulics, plus the loader linkage and buckets. The System Testing section is the part shops live in: seven-step diagnosis, hydraulic test specs on page 1227, a printed electrical schematic and wiring diagram at pages 1199-1200, and a fold-out closed-centre hydraulic schematic at page 1305. The scan is the paper book, fully legible page by page.
What's Inside This John Deere 644C Manual
| System | Pages | Key Topics |
|---|---|---|
| General Information | 5-36 | Safety Information, General Specifications for Both Machines, Hardware Torque Charts, Fuels and Lubricants |
| Wheels | 37-46 | Powered Wheels and Fastenings, Wheel Removal and Installation, Wheel Nut Torque |
| Axles and Suspension Systems | 47-158 | Differential and Bevel Drive, Input Drive Shafts and U-Joints, Axle Shafts, Bearings and Reduction Gears, Axle Hydraulics |
| Transmission | 159-288 | Removal and Installation, Controls, Input Drive Shafts, Gears, Shafts, Bearings and Power Shift Clutch, Transmission Hydraulics |
| Engine | 289-552 | Crankshaft and Main Bearings, Camshaft and Valve Actuating Means, Connecting Rods and Pistons, Cylinder Block, Oiling and Ventilating Systems, Cylinder Head and Valves, Fuel Injection, Turbocharger, Water Pump, Starting Motor, Flywheel |
| Engine Auxiliary Systems | 553-600 | Cold Weather Starting Aids, Cooling Systems, Speed Controls, Intake System, External Exhaust, Mounting Frame, External Fuel Supply |
| Torque Converter | 601-652 | Turbine, Gears, Shafts and Bearings |
| Steering System | 653-724 | Emergency Steering, Steering Hydraulics |
| Service Brakes | 725-767 | Active Elements, Controls Linkage, Brake Hydraulics |
| Parking and Emergency Brakes | 768-784 | Active Elements and Controls Linkage |
| Electrical Systems | 785-820 | Batteries, Support and Cables, Alternator, Regulator and Charging System Wiring, Lighting System, Wiring Harness and Switches, System Controls, Instruments and Indicators |
| Frame, Chassis and Supporting Structure | 821-846 | Frame Installation, Frame Bottom Guards, Chassis Weights |
| Operator's Station | 847-922 | Removal and Installation, Operator Enclosure, Seat and Seat Belt, Heating and Air Conditioning |
| Sheet Metal and Styling | 923-940 | Hood and Engine Enclosure, Grille and Grille Housing, Fenders |
| Safety, Convenience and Miscellaneous | 941-950 | Mirror, Fire Extinguisher, Horn and Warning Devices, Cigar Lighter |
| Main Hydraulic System | 951-1018 | Closed-Centre Main Hydraulic System, Pump, Valves and Lines |
| Loader | 1019-1134 | Buckets, Controls Linkage, Frames, Loader Hydraulics |
| System Testing | 1135-1336 | Seven Basic Steps of Diagnosis, Engine Testing, Electrical Testing with the Electrical Schematic and Wiring Diagram, Power Train Testing, Hydraulic Testing with the Closed-Centre Schematics, Heating and Air Conditioning Testing |
| Special Tools | 1337-1378 | Dealer-Made and Service Tools Illustrated in Numerical Order |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| 644C Loader and 646C Compactor, turbocharged and intercooled diesel | ||
| Rated power, SAE net at 2200 rpm | 152 hp (113 kW) | p. 13 |
| Both machines | ||
| Piston displacement | 466 cu. in. (7.836 L) | p. 13 |
| Maximum torque at 1300 rpm | 472 lb-ft (640 N·m) | p. 13 |
| All Models | ||
| Wheel nut torque | 300 ± 30 lb-ft (410 ± 40 N·m) (644C Loader) / 450 ± 45 lb-ft (610 ± 61 N·m) (646C Compactor) | p. 39 |
| Boom raise cycle time | 6.1 to 6.8 seconds (644C Loader at 2400 rpm, oil 150 to 190 °F; slower than 7.6 seconds indicates a hydraulic problem) / 6.5 to 7.2 seconds (646C Compactor at 2400 rpm, oil 150 to 190 °F; slower than 8.1 seconds indicates a hydraulic problem) | p. 1231 |
| Fast idle, oil at 150 ± 10 °F (66 ± 6 °C) | ||
| Hydraulic pump standby pressure | 2350 ± 50 psi (16 203 ± 345 kPa) | p. 1227 |
| 2000 ± 10 rpm at 2000 psi, oil at 150 ± 10 °F | ||
| Hydraulic pump minimum flow, new or rebuilt | 30 gpm (113 L/min) | p. 1227 |
| Hydraulic pump minimum flow, used pump | 24 gpm (91 L/min) | p. 1227 |
| Slow idle, oil at 195 ± 10 °F | ||
| Differential lock pressure | 600 ± 75 psi (4137 ± 517 kPa) | p. 1227 |
| Engine stopped, oil at 100 to 150 °F | ||
| Emergency steering pressure switch setting | 700 psi (4830 kPa) | p. 1228 |
| Fast idle, oil at 150 ± 10 °F | ||
| Converter-out pressure | 40 to 85 psi (276 to 586 kPa) | p. 1229 |
| Transmission pump minimum flow | 22 gpm (83 L/min) | p. 1229 |
| 644C Loader at 2400 rpm, oil 150 to 190 °F | ||
| Bucket dump cycle time | 1.5 to 2.2 seconds | p. 1231 |
John Deere 644C Common Problems This Manual Covers
Boom raise slower than spec, weak breakout, hydraulics fade when hot
Run the page 1231 cycle-time checks first (644C boom limit 7.6 seconds, 646C limit 8.1), then flow-test the pump against page 1227: 24 gpm minimum for a used pump at 2000 rpm and 2000 psi, standby 2350 +/- 50 psi. The System Testing hydraulic procedures and the fold-out closed-centre schematic at page 1305 walk the whole circuit; pump overhaul is in Main Hydraulic System.
Manual Section: System Testing (pages 1135-1336) with Main Hydraulic System (pages 951-1018) p. 1231Loss of drive or sluggish response through the torque converter and power shift transmission
Check converter-out pressure at fast idle against the 40 to 85 psi spec and transmission pump flow against the 22 gpm minimum, both on page 1229, before pulling anything. Pressure out of range sends you to the Torque Converter section for turbine, gears and bearings, or to Transmission for the power shift clutch and transmission hydraulics.
Manual Section: System Testing power train tests (page 1229), Transmission (pages 159-288), Torque Converter (pages 601-652) p. 1229Differential lock will not hold in soft ground or on the landfill face
Test lock pressure at slow idle with oil at 195 +/- 10 F against the 600 +/- 75 psi spec on page 1227. If pressure is right but the lock still slips, the Axles and Suspension Systems section covers teardown of the differential and bevel drive, axle shafts, bearings and reduction gears with full specs.
Manual Section: System Testing hydraulic specifications (page 1227), Axles and Suspension Systems (pages 47-158) p. 1227Steering goes heavy, or the emergency steering does not cut in when it should
The Steering System section covers emergency steering and steering hydraulics with removal, repair and adjustment. Verify the emergency steering pressure switch against its 700 psi (4830 kPa) setting on page 1228, then pressure-test the steering circuit per the System Testing procedures. On a machine this heavy, an out-of-adjustment switch means no backup steering exactly when the engine dies.
Manual Section: Steering System (pages 653-724), System Testing (page 1228) p. 1228Frequently Asked Questions
My 644C boom is getting slow. Does this manual tell me whether the pump is worn out or I have another problem?
Yes, and with hard numbers. Page 1231 gives boom raise cycle times: 6.1 to 6.8 seconds for the 644C at 2400 rpm with oil at 150 to 190 F, and anything slower than 7.6 seconds means a hydraulic problem (646C spec is 6.5 to 7.2, limit 8.1). Page 1227 then gives the pump pass/fail: a used pump must still make 24 gpm at 2000 rpm and 2000 psi, new or rebuilt 30 gpm, with standby pressure at 2350 +/- 50 psi. Stopwatch first, flow meter second, and you know whether you are buying a pump. p. 1231
Does it cover a complete engine rebuild on the 466 diesel?
Yes. The Engine section runs about 260 pages (289-552) and covers crankshaft, camshaft and valve train, rods and pistons, cylinder block, oiling, head and valves, fuel injection, turbocharger, water pump, starter and flywheel. Baseline specs are on page 13: 152 hp SAE net at 2200 rpm, 466 cu. in. (7.836 L), 472 lb-ft peak torque at 1300 rpm. Cooling, cold weather starting aids and intake/exhaust are in the Engine Auxiliary Systems section, pages 553-600. p. 289
The machine loses drive or feels weak through the transmission. Is the power shift and torque converter serviced here?
Both, fully. Transmission removal, controls, gears, shafts, power shift clutch and transmission hydraulics are at pages 159-288, and the torque converter (turbine, gears, shafts, bearings) at pages 601-652. Before tearing anything down, use the power train tests: page 1229 gives converter-out pressure of 40 to 85 psi at fast idle and a transmission pump minimum of 22 gpm at fast idle. Low converter-out pressure points you at the cause instead of a guess. p. 1229
There are no fault codes on a machine this age. How does the book handle electrical problems?
The 1980s way, which still works: a printed electrical schematic and wiring diagram at pages 1199-1200 in System Testing, plus the Electrical Systems section (pages 785-820) for batteries and cables, alternator, regulator and charging circuit wiring, lighting, harness, switches and gauges. You trace circuits with a test light or meter against the diagram. Charging and lighting faults on these machines come down to continuity and connections, and the diagram makes that a methodical job. p. 1199
Are the wheel torques different between the loader and the compactor?
Yes, and it matters because the 646C runs compactor wheels. Page 39 gives 300 +/- 30 lb-ft (410 +/- 40 N.m) for the 644C loader and 450 +/- 45 lb-ft (610 +/- 61 N.m) for the 646C compactor. General hardware torque charts, fuels and lubricants are in the General Information section, pages 5-36. The scan is fully legible page by page; it has no clickable bookmarks, so navigate by the section page ranges. p. 39
Which manual sections cover the loader end itself, buckets and linkage?
The Loader section, pages 1019-1134: buckets, controls linkage, frames and loader hydraulics. It works together with the Main Hydraulic System section (pages 951-1018) covering the closed-centre pump, valves and lines. For checking loader health, page 1231 gives cycle times including bucket dump at 1.5 to 2.2 seconds on the 644C, so you can judge cylinders and valve work with a stopwatch before opening anything. p. 1019
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