1990–1999 John Deere 670, 770, 790, 870, 970, 1070 Compact Utility Tractor Technical Manual (P/N TM1470)

John Deere technical manual P/N TM1470 covers the 1990–1999 670, 770, 790, 870, 970, and 1070 Compact Utility Tractors. The cover is dated March 15, 1999, and identifies this edition as replacing the March 15, 1994 publication.

• Engine repair and testing: Engine removal and installation, dedicated 790 internal engine repair, compression testing, oil-pressure checks, and cooling-system diagnosis.

• Clutch and transmission service: Single- and dual-stage clutch repair, transmission disassembly, shift-linkage adjustment, and rear and mid mount PTO service.

• MFWD and final drives: Front-drive axle disassembly, differential cone-point and backlash adjustments, and spur-gear and planetary final-drive repair.

• Steering and brakes: Manual and power steering repair, hydraulic leakage tests, dry shoe brake service, and wet disk brake inspection.

• Hydraulic diagnosis: Pump and rockshaft repair, Selective Control Valve service, relief-valve and flow tests, and 1070 draft-control adjustments.

• Electrical troubleshooting: Serial-specific cranking and fuel shut-off test charts, charging-system checks, safety-interlock diagnosis, and electrical schematics.

This manual is written for experienced technicians and identifies the essential tools required for specific service work.

Engine Repair and Fuel-System Coverage

The engine sections distinguish the Yanmar TN-series engines from the 790’s TNE-series engine. The dedicated 790 chapter covers cylinder-head and valve work, pistons and rings, crankshaft and main bearings, camshaft inspection, timing gears, and oil-pump service. Wear limits and inspection specifications accompany the repair procedures.

Component-manual requirement: Complete internal engine repair for the 670, 770, 870, 970, and 1070 requires the separate CTM-3 component manual, which is not included. Their injection-pump, nozzle, and governor repair information also refers to that publication.

For the 790, fuel-system coverage includes pump removal and installation, injection-nozzle disassembly and testing, static injection timing, and fuel-system bleeding. Internal injection-pump and governor repairs are assigned to a qualified fuel-injection repair shop.

Cooling-system procedures include radiator inspection, pressure testing, and thermostat checks. Engine diagnostic charts address hard starting, irregular running, smoke, low power, overheating, and oil-pressure complaints.

Transmission, MFWD, and PTO Repair

The power train sections separate the 670/770/790 assemblies from the larger tractor group. They distinguish spur-gear final drives from planetary assemblies and provide separate MFWD axle procedures for the 870 and 970/1070.

Clutch instructions include model-specific alignment and finger-adjustment information. Tool references include the JDG693 alignment tool for 670/770/790 dual-stage clutches and the JDG52 PTO clutch-finger gauge for the 870/970/1070.

The manual warns that the rear PTO connecting-shaft coupling can drop into the transmission housing during separation of a dual-stage-clutch tractor, requiring rockshaft removal to retrieve it.

Working with pressurized hydraulics and heavy powertrain components carries inherent risks. Review the general machine information and safety guidelines before starting a teardown.

Steering, Hydraulics, and Mower Components

Power steering coverage extends to valve, cylinder, and pump repair, with leakage and pump-flow tests. Brake procedures distinguish the smaller models’ dry shoe assemblies from the larger models’ wet disk brakes.

Hydraulic diagnostic charts separate tractors with and without an SCV. Pump-flow, relief-valve, rockshaft-leakage, and lift-cycle tests help distinguish inadequate pump delivery from leakage or control-valve faults.

SCV repair illustrations distinguish early Kanzaki and Danfoss/Dukes assemblies. The 1070 sections cover position-feedback and draft-sensing linkages; the feedback-adjustment section warns that insufficient lift-arm free travel can overheat the hydraulic oil and cause damage.

Mower coverage includes spindle and gearbox disassembly, inspection, and assembly for 50-, 60-, and 72-inch mowers, with separate early- and late-model gearbox section views.

Electrical Test Charts and Circuit Drawings

Cranking System Test Points and fuel shut-off circuit checks distinguish old and new electrical versions by serial number. This helps select the applicable interlock circuit before tracing a no-start or engine shut-off complaint.

Drawings include the Electrical Schematic—Old Version, Electrical Schematic—New Version, and 670 European Electrical Schematic. Separate 670/770/790 and 870/970/1070 hydraulic schematics show SCV, rear auxiliary outlet, steering, and rockshaft circuits.

Examples of Engine Torque and Adjustment Data

These examples are a small selection of the model-specific repair specifications in the manual.

For the 790, the cylinder-head section specifies a final bolt torque of 85–91 N·m with lubricating oil applied, together with staged tightening in the illustrated sequence. Valve clearance is specified at 0.15–0.25 mm with the engine cool at room temperature.

For the 870, 970, and 1070, the engine-to-clutch housing cap screws are specified at 113 N·m.

PDF Search, Schematic Detail, and Included Pages

Text search and diagram navigation: Text search works across many written sections, but several diagrams and their labels are not searchable. Embedded bookmarks cover the main sections and many individual procedures; one electrical-component entry lacks a destination. Small wiring labels require zooming, and some lettering and wire codes in the 670 European schematic remain difficult to read when enlarged.

The download contains one printable, English-language 1,020-page PDF. That total already includes the cover, five foreword and contents pages, two index pages, and ten enlarged electrical and hydraulic schematic detail pages.