1978-1987 John Deere 670A/672A Motor Grader Repair Manual

John Deere 670A/672A Service Manual — 1978–1987 Technical Coverage

• Covers 1978–1987 John Deere 670A and 672A motor graders, including the JD672A front-wheel drive hydrostatic system and standard tandem drive components
• Official John Deere publication TM-1188, revised December 1987
• Documents technical specifications for 14 primary sub-systems, including hydraulic cycle times, electrical system schematics, and drivetrain torque values
• Delivered as a direct download the moment payment clears
• Full-text search finds any part number in seconds
• This 1987 revision includes critical updates for Weather Pack electrical connectors and radial piston pump CTM-7 assembly

Technical Scope and Data

This technical manual documents the repair, assembly, and testing of the 1978–1987 John Deere 670A and 672A motor graders. It provides specific guidance on engine auxiliary systems, transmission controls, transfer drive housings, and steering system hydraulics. Service technicians can utilize the detailed segment on power-shift transmission and planetary gear reduction to facilitate component inspection and maintenance. The publication also catalogs the frame and operator station configurations for these specific units.

Specifications and Maintenance Data

Technical data provided includes capacity limits for fuel, engine lubrication, and cooling systems. Detailed hardware torque tables are specified for structural fasteners such as the tandem housing and articulation pivot pins. Fluid pressure thresholds for the hydraulic system and hydrostatic charge are listed to assist in system diagnosis. What factory workshop documentation is structured specifically to help users identify system tolerances and clearance values during maintenance tasks.

Coolant system capacity for the 1978–1987 John Deere 670A and 672A is documented at 7 gallons (26.5 liters). The standard operating engine speed for these units is 2300 RPM. Differential lock pressure is specified at 635 psi with shims adjusting the setting by 31 psi increments.

Note: This page is a contents overview for the manual. It does not provide repair or diagnostic instructions.

An official 774-page John Deere OEM technical manual covering the 1978–1987 John Deere 670A/672A, documenting engine, hydraulic, electrical, and drivetrain specifications for these heavy-duty motor grader models.