1985–1987 John Deere 444D, 544D, and 644D Loader Operation and Tests Manual (P/N TM-1341)

John Deere technical manual TM-1341, October 1987 revision, covers operation, diagnosis, testing and adjustment for the 1985–1987 444D, 544D and 644D loaders, with specific checks and test data for the 544D Feller-Buncher.

• Engine diagnostics: Cooling, lubrication and fuel-injection operation, compression and boost tests, injection-pump timing, valve-clearance adjustment, and idle settings.

• Electrical troubleshooting: Serial-specific starting, charging, gauge and accessory circuit checks, wiring diagrams, connector locations, and electrical test specifications.

• Power train: Twin-turbine torque converter and planetary powershift operation, clutch-leakage tests, transmission pressure checks, and control-linkage adjustment.

• Brakes and differentials: Inboard wet-disk brake checks, brake bleeding, accumulator charging, and hydraulic differential-lock pressure and leakage tests.

• Loader hydraulics and steering: Pump-flow testing, cylinder drift and leakage checks, relief-valve tests, return-to-dig controls, and secondary steering diagnosis.

• Heating and air conditioning: R-12 system diagnosis, expansion-valve and temperature-control-switch tests, compressor-oil checks, evacuation, and charging procedures.

Written for experienced service technicians, this manual assumes familiarity with machine service and the specified diagnostic equipment.

Operational Checkout and Engine Diagnostics

System operational checks lead into malfunction charts and targeted tests. Engine coverage addresses hard starting, surging, low power, fuel-supply restrictions, cooling faults and lubrication problems.

Model-specific fuel-injection pump and nozzle descriptions explain fuel delivery, including nozzle opening-pressure information for the 644D. Test procedures cover compression, transfer-pump pressure, turbocharger shaft movement, boost pressure and radiator airflow. Equipment references include the JT39000 tachometer and D-01084AA tachometer/temperature reader.

Engine repair scope: Internal engine work and injection-pump servicing are referred to separate repair sections and component manuals. This Operation and Tests volume does not provide a complete engine-overhaul procedure.

Electrical Circuits Before and After the Serial Break

Electrical coverage separates machines through Serial No. 512188 from those starting at 512189. The later machines use a revised wire-numbering and color-coding system, helping technicians match a circuit and connector test to the correct harness before tracing a fault.

Starting Circuit pictorials and the Clutch Cut-Off, Differential Lock, Boom Kickout and Return-to-Dig Wiring Diagram support circuit diagnosis. Component-location drawings, ground-location information and voltage-drop tables add detail beyond the circuit descriptions.

Transmission, Brake and Differential Tests

Power-flow block diagrams and the Transmission Assembly Cross Section explain the turbine and range-clutch torque paths. The Transmission and Brake Hydraulic System Schematic connects the pressure-regulating, clutch cut-off, lubrication and brake circuits.

Procedures cover torque-converter stall testing, transmission-element leakage checks, oil-cooler restriction and backflushing, brake-pad inspection, and service- and parking-brake linkage adjustment. Internal transmission repairs, including clutch-pack work, are referred to separate repair sections.

The brake-accumulator procedure specifies dry nitrogen and warns that charging too rapidly can dislodge the gas-check-valve seal.

Loader Hydraulics and Steering

The hydraulic chapters distinguish early pilot-operated relief valves from later direct-acting valves. Pump-flow and relief-valve test data also distinguish the 544D Feller-Buncher from loader configurations.

The Hydraulic System Schematic supports priority-valve and steering-circuit diagnosis. Further procedures address boom, bucket and multipurpose-bucket clam leakage, secondary-steering check valves, and contaminated-oil cleanup with a portable filter caddy.

The steering-stop inspection and frame-stop repair guidance address deformed stops that can let the piston strike the rod guide and damage the steering cylinder. High-pressure fluids and crush hazards require the manual's pressure-relief and raised-equipment support precautions.

Heating and R-12 Air Conditioning

The Operating Pressure Diagnostic Chart relates gauge readings and sight-glass conditions to refrigerant loss, restrictions and control faults. Expansion-valve and temperature-control-switch bench tests accompany leak-testing and system-service procedures for the original R-12 installation.

A Preview of Cooling, Idle and Axle Specifications

These figures are a small selection of the manual's capacity, adjustment and inspection data. Reference tables also list transmission pressure ranges and ground-level lift capacity.

The torque tables distinguish dry-thread customary hardware torques from metric hardware torques specified with SAE 30W oil on the threads.

The 444D cooling-system refill capacity is 24 U.S. qt (23 L). The revised 644D slow-idle specification is 900 ± 25 rpm with the engine at normal operating temperature.

The axle-bearing check specifies a maximum axle-shaft movement of 0.015 in. (0.38 mm), measured with a dial indicator.

PDF Bookmarks, Diagram Viewing and Page Count

Search, bookmarks and diagrams: The PDF is partially searchable through an OCR text layer. Some text and diagram pages have no searchable text. Embedded bookmarks cover the main sections and numerous individual tests. Small wire IDs and foldout labels require magnification.

The download contains one printable, English-language, 599-page PDF. That total comprises 564 content pages, one cover, one revision-notice page, one closing copyright page, and 32 blank or header/footer-only pages.