John Deere 401D Tractor 1984 Technical Manual (P/N TM-1271)

John Deere Technical Manual P/N TM-1271 (OCT-84) covers repair and system testing for the 401D Tractor, including its loader, backhoe, and PTO configurations.

Searchable Repair Text, Bookmarks, and Foldout Diagrams

Text search and diagram detail: An embedded OCR text layer supports searches through much of the repair text, but some diagram and system-operation pages are not searchable. Embedded bookmarks provide access to sections, specifications, and individual procedures. Small wiring labels generally require zooming; some labels remain faint even when enlarged.

One printable PDF in English contains 1,404 pages, including the original front cover, two unnumbered blank pages, and the rear safety cover. Numbered blank pages within the manual are also included.

Engine, Drivetrain, and Implement Service

The following selected contents outline the main repair areas rather than reproduce the complete contents list. Further topics include cold-weather starting aids and three-point-hitch service.

• Engine repair: Engine removal and installation, crankshaft and main-bearing inspection, cylinder-liner and cylinder-head work, timing gears, lubrication, cooling, and fuel-system service.

• Power train and PTO: Transmission and reverser overhaul, rear final drives, single- and dual-stage clutches, plus continuous, mid-mount, and independent PTO arrangements.

• Main hydraulics: Separate main-pump configurations, pressure- and stroke-control valves, accumulator overhaul and charging, selective-control valves, remote cylinders, and rockshaft repair.

• Steering, brakes, and front axle: Hydrostatic steering repair, wet-disc brake inspection, brake-valve overhaul, bleeding, parking-brake service, wheel hubs, spindles, and axle adjustments.

• Loader and backhoe: Self-leveling and non-self-leveling loader configurations, the 9250B backhoe, control valves, structural components, hydraulic cylinders, and cylinder-drift diagnosis.

• Electrical diagnosis: Starting and charging tests, lighting, gauges, indicators, wiring diagrams, and configuration-specific wire-routing descriptions.

This manual was written for experienced service technicians; it assumes familiarity with shop service and the specified testing and support equipment.

Engine, Cooling, and Fuel-System Work

The engine chapters provide step-by-step procedures for removal, installation, and break-in. Internal work includes crankshaft end play and bearing-clearance checks, camshaft inspection, piston and connecting-rod service, cylinder liners, cylinder-head and valve repair, and the balancer shaft.

Supporting chapters cover the oil pump, water pump, thermostat, oil cooler, fuel transfer system, and starting-motor overhaul. Engine testing includes compression, oil pressure, cooling-system checks, fuel-transfer pressure, and injection-pump timing advance.

Injection-system limits: Pump removal, installation, drive-shaft service, timing, nozzle removal and installation, and fuel-system bleeding are included. Internal injection-pump repair is referred to SM-2045, while nozzle repair is referred to TM-1214; those separate manuals are not included.

Transmission, Reverser, and Major Tractor Splits

The power-train sections cover tractor separation, transmission and axle removal, clutch-housing removal, reverser clutch-pack inspection, reverser brake and planetary repair, and control-valve service.

Separate transmission oil-pump procedures distinguish units with neither a reverser nor independent PTO, units with independent PTO, and units with a reverser. Differential preload and backlash, shifter installation, parking-brake or park-lock arrangements, PTO shaft setup, and clutch-linkage and lever adjustments are documented.

Assembly details: Reverser and PTO separator plates have an intentional wavy shape; flattening them can interfere with pack operation. The planetary assembly also has roller-set requirements and etched gear-timing marks that matter during reassembly.

Access chapters cover ROPS or canopy, fender, platform, seat, cowl, and battery-box removal and installation for major splits.

Pump Overhaul and Hydraulic Fault Isolation

The hydraulic section distinguishes the 23 cm³ (1.38 cu in.) and 50 cm³ (3.0 cu in.) main pumps. Repair coverage includes internal inspection, reassembly, pump drives, the larger pump’s stroke-control valve, pressure-control valves, and selective-control-valve adjustment.

Accumulator procedures include overhaul and nitrogen charging. The hydraulic filter, reservoir, remote cylinders, and rockshaft assembly have their own service material.

Factory testing: Flow-meter and hydraulic-analyzer procedures address the transmission pump and both main pumps. Further tests cover system leakage, standby pressure, surge and cooler relief valves, reverser and clutch-control pressure, brake valves, steering, and loader/backhoe cylinder drift.

The Closed-Center Hydraulic System Test Record and Test Pattern Analysis Charts connect measured results with probable causes and verification checks. This gives the technician a way to distinguish restrictions, leakage, and pump faults before selecting a component for teardown.

Loader, Backhoe, and Cylinder Repair

Loader chapters cover bucket and cutting-edge work, control linkage, boom and side-frame removal, bushings, valve teardown, relief valves, and final installation. Cylinder procedures distinguish cap-seal and V-packing designs, including the cap-seal boom cylinder used with the self-leveling bucket.

The backhoe chapters add removal and installation, bucket teeth and shanks, boom and dipperstick repair, swing-frame and stabilizer work, control linkage, and quick-connect adapters. Valve and cylinder service covers the boom, crowd, bucket, stabilizer, and swing functions.

Cylinder assembly notes address seal orientation and protection against cutting during installation. Rear-axle brake procedures also address pressure-plate packing protection.

Electrical Schematics, Section Views, and Shop References

The 12-volt electrical material covers batteries, alternator repair, switches, gauges, indicators, and circuit testing. Electrical Schematic, Electrical Diagram, and wire-routing references distinguish parking-brake/four-post ROPS units from two-post ROPS units without a parking brake.

Engine and power-train Component Location Drawings accompany the diagnostic sections. Hydraulic System Schematics distinguish tractors with and without a reverser, loader, and backhoe. Cross-sections show the steering valve and cylinder, main pumps, stroke-control valve, accumulator, and loader/backhoe valve and cylinder assemblies.

Tools and specifications: Callouts include the JD-281 engine timing tool, JD-358 torque-wrench adapter, D-01080AA hydraulic analyzer, and D-15051NU flow meter. Section 99 illustrates tools and dealer-fabricated fixtures and wrenches, including a liner-holding fixture and injection-pump wrench.

Reference data includes customary Grade B, D, and F hardware charts, metric hardware torque charts, component torques, spring-test specifications, bearing clearances and end play, preload and backlash settings, inspection limits, lubricants, and electrical test values.

Crankshaft and Main-Bearing Specification Examples

Crankshaft end play with new parts is 0.10–0.20 mm (0.004–0.008 in.), with a maximum allowable value of 0.38 mm (0.015 in.). New main-bearing clearance is 0.04–0.12 mm (0.002–0.005 in.); maximum allowable clearance is 0.15 mm (0.006 in.).

Before starting any repair, lower and support raised equipment, relieve hydraulic pressure, stop the engine, isolate the battery, and use lifting and support equipment rated for the component. High-pressure fluid and the loader, backhoe, transmission, axle, and ROPS assemblies can cause severe injury if the factory preparation and support procedures are skipped.