Part of the John Deere Repair Manuals.
Need factory procedures for your 1987 John Deere 670A or 672A Motor Grader? This 774-page John Deere 670A repair manual PDF (OEM TM-1188) breaks down both machines front to back, from the power shift transmission and tandem drive axles to the circle gearbox and blade controls. You get step-by-step teardown and rebuild procedures for every system: engine removal, power steering, transfer drive, service and parking brakes, and the main hydraulic system, backed by exploded views and a full troubleshooting section. Torque tables and factory specs run through all of it. Set the transmission oil filter cap screw to 45 lb-ft (61 Nm) and hold output gear end play at 0.002 ± 0.002 in. Graders this old don't forgive guesswork. Bookmarked by system and keyword-searchable; download it, find the number, and get that blade cutting grade again.
What's Inside This John Deere 670A, 672A Repair Manual
| System | Pages | Key Topics |
|---|---|---|
| Introduction | 7-10 | Fos Manuals for Reference, Technical Manuals for Actual Service, General Specifications and Services, Removal, Repair, Testing, System Operation, Diagnosis |
| General Information | 11-70 | General Specifications, Predelivery, Delivery, And After-Sale Service, Lubrication |
| Wheels | 71-78 | Power Wheels and Fastenings, Non-Powered Wheels and Fastenings |
| Axles and Suspension System | 79-186 | Drive Axle Housing and Support, Differential or Bevel Drive, Non-Power Wheel Axles, Axle Shafts, And Reduction Gears, Bearings, Hydraulic System |
| Transmission | 187-268 | Controls, Housings and Covers, Bearings and Power Shift Clutch, Clutch Disconnect and Controls, Gears, Shafts, Hydraulic System |
| Engine | 269-304 | Removal and Installation, Starting Motor and Fastenings |
| Engine Auxiliary System | 305-322 | Cold Weather Starting Aids, Engine Cooling System, Speed Controls, Intake System, Mounting Frame, External Fuel Supply System |
| Transfer Drive | 323-342 | Housing and Covers, Gears, Shafts, Bearings |
| Steering System | 343-378 | Power Steering, Hydraulic System |
| Service Brakes | 379-398 | Active Elements, Controls Linkage, Hydraulic System |
| Parking-Emergency Brakes | 399-412 | Active Elements, Controls Linkage |
| Equipment Attaching | 413-418 | Drawbar |
| Electrical System | 419-496 | Batteries, Support and Cables, Alternator, Regulator and Charging System Wiring, Lighting System, Wiring Harness and Switches, System Controls, Instruments and Indicators |
| Frame, Chassis or Supporting Structure | 497-510 | Frame Installation, Bottom Guards, Vehicle Bumpers |
| Operator's Station | 511-568 | Operator Enclosure, Seat and Seat Belt, Steps and Handholds, Heating and Air Conditioning, Specifications and Tools |
| Sheet Metal | 569-580 | Hood or Engine Enclosures, Miscellaneous Shields, Grille and Grille Housing |
| Safety, Convenience and Miscellaneous | 581-590 | Mirrors, Fire Extinguisher, Horn, Cigar Lighter |
| Main Hydraulic System | 591-668 | Hydraulic System |
| Grading Device | 669-738 | Blade, Grading Device Frames, Circle Gearbox, Controls Linkage, Hydraulic System |
| Ground Conditioning Tools | 739-774 | Teeth and Shanks, Frames, Controls Linkage, Hydraulic System |
Every system also includes specifications and special tools.
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Batteries, Support and Cables | Group 1671 | p. 6 |
| Transmission oil filter cap screw torque | 45 lb-ft (61 Nm) (6 kg-m) | p. 241 |
| Transmission oil filter element replacement | at regular time intervals or whenever clogged | p. 241 |
| End play adjustment for output gear | 0.002 ± 0.002 in. (0.05 ± 0.05 mm) | p. 335 |
| End play adjustment for idler gear | 0.002 ± 0.002 in. (0.05 ± 0.05 mm) | p. 334 |
| Battery electrolyte level check | every 50 hours | p. 64 |
| Battery Volts | 12 | p. 421 |
| Tighten special cap screw (1) | 15 to 20 lb-ft (20 to 27 N·m) (2 to 3 kg-m) | p. 603 |
| Engine Net Power | 125 hp (93.2 kW) | p. 11 |
| Engine Piston Displacement | 414 cu. in. (6784 cm3) | p. 11 |
| Transmission Oil Temperature (Normal Operating Range) | 100-222°F (38-105°C) | p. 21 |
| Tandem Wheel Cap Screws Torque | 300 lb-ft (407 Nm) (42 kg-m) | p. 33 |
John Deere 670A, 672A Common Problems This Manual Covers
John Deere 670A engine cranks slowly or won't start, starter clicks in cold weather
Test battery specific gravity with a hydrometer; full charge reads 1.260 corrected to 80°F (27°C), and more than 0.050 points variation between cells means replace it. Run a high-rate discharge test and confirm each cell holds at least 9.0 volts, using the specs on page 481. Clean both terminals and verify the negative ground cable is tight.
Manual Section: Electrical System p. 481Hydraulic system loses pressure under load, blade drifts or moves erratically during grading
Replace the hydraulic oil filter first; a clogged element starves the pump and makes the blade jerk. Torque the filter's special cap screw to 15 to 20 lb-ft (20 to 27 N·m) as shown on page 603. If pressure stays low, inspect the pump drive assembly and retorque the pump support cap screws to 85 lb-ft (115 N·m).
Manual Section: Main Hydraulic System p. 603Transmission slips between gears or won't engage after sitting, oil smells burnt
Check transmission oil temperature under load; the gauge should hold in the 100-222°F (38-105°C) normal range shown on page 21. Drain the old oil, replace the filter element, and torque the filter cap screw to 45 lb-ft (61 Nm) per page 241. If slipping continues with fresh oil and a new filter, suspect worn clutch packs.
Manual Section: Transmission p. 241Differential lock fails to engage on soft ground, one drive wheel spins freely in the cut
Connect a gauge and run the differential lock valve pressure test on page 62. Verify the reading falls at 635 ± 25 psi (44 ± 1.7 bar); add or remove shims until it does. Check axle oil level and condition while the gauge is hooked up, since low or contaminated oil ruins the lock clutch.
Manual Section: Axles and Suspension System p. 62Tandem wheel cap screws keep loosening, wheel wobble shows up at transport speed
Retorque all wheel retaining cap screws on the JD670-A, and rear wheel cap screws on the JD672-A, to 300 lb-ft (407 Nm) following page 33. On the JD672-A only, tighten front wheel cap screws to 130 lb-ft (177 Nm). Inspect stud holes for elongation and replace any wheel that loosens again after a proper torque.
Manual Section: Wheels p. 33Frequently Asked Questions
What are the recommended service intervals?
The manual refers to a periodic service chart located on the motor grader's right engine side shield for recommended service intervals. For example, the engine oil and filter should be changed after the first 100 hours, and then every 200 hours thereafter. p. 50
What fluids and capacities does this machine require?
The machine requires various fluids with specific capacities. For example, the fuel tank capacity is 60 gal. (227 L), the cooling system is 7 gal. (26.5 L), and the engine lubrication (including filter) is 20 qt. (18.9 L). p. 11
How to troubleshoot engine won't start?
If the engine fails to operate with a low current draw, it could be due to an open series field circuit, open armature coils, or defective brush contact with the commutator. If it fails to operate with a high current draw, it might be due to grounded terminals or fields, or seized bearings. p. 283
What torque specifications are listed?
The manual lists various torque specifications for different components. For instance, powered tandem wheel cap screws should be tightened to 300 lb-ft (407 Nm) (41 kg-m), and powered front wheel cap screws to 130 lb-ft (175 Nm) (18 kg-m). p. 77
How to reset error codes or warning lights?
Circuit breakers, which protect the electrical system and can cause warning lights, reset automatically when the temperature at the breaker decreases after tripping. p. 458
How will I receive this John Deere 670A, 672A, JD670-A, JD672-A Repair Manual?
Instant PDF download. You get the full 774-page searchable Repair Manual immediately after payment. Open it on your laptop, tablet, or phone right in the shop.
Can I print this manual?
Yes. The PDF has no DRM restrictions, so print any page or section you need for your shop. Works with any standard printer.
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