The Ford / New Holland 40 Series became one of the best-known tractor ranges of the 1990s. Models such as the 5640, 6640, 7740, 7840, 8240 and 8340 combined proven mechanical components with increasingly sophisticated powershift, hydraulic and electronic control systems.
This guide covers the Ford and New Holland 40 Series in general. Exact engines, transmissions, EDC hydraulics, PTO systems, electronic controls, fault codes and wiring vary by model, specification and serial range. Use the correct workshop manual and electrical manual for the exact tractor.
1. The 40 Series Range
Common models include:
- 5640
- 6640
- 7740
- 7840
- 8240
- 8340
There are also regional, specification and market variations.
2. Ford to New Holland Branding
Tractors from this period may carry Ford or New Holland branding depending on production date and market.
Do not assume different bonnet graphics mean completely different mechanical systems.
3. Identification Before Repair
Record:
- Exact model
- Serial number
- Engine identification
- Transmission type
- Hydraulic specification
- PTO type
- Cab/electrical option level
Running changes affect sensors, controllers, solenoids, wiring, transmission components and hydraulic settings.
4. Diesel Engines
The range uses robust diesel engines suited to agricultural work.
When assessing one, check:
- Cold starting
- Oil pressure
- Blow-by
- Exhaust smoke
- Fuel leaks
- Coolant condition
5. Hard Starting
Before blaming the injection pump, check:
- Battery condition
- Starter speed
- Fuel filters
- Air in fuel system
- Cold-start equipment
- Compression
- Injection timing
6. Fuel Injection System
Depending on engine and year, systems remain largely mechanical compared with later common-rail tractors.
Common issues include:
- Blocked filters
- Air leaks
- Lift-pump weakness
- Injector wear
- Fuel shut-off faults
7. White Smoke at Start-Up
Possible causes include:
- Low compression
- Slow cranking
- Incorrect timing
- Poor injector spray
- Cold combustion chamber
8. Black Smoke Under Load
Check:
- Air filter
- Turbo/boost hoses where fitted
- Fuel delivery
- Injector condition
- Engine load
9. Turbocharger System
Higher-powered models may use turbocharging.
Check:
- Boost hoses
- Intercooler where fitted
- Turbo oil feed/drain
- Exhaust leaks
- Compressor condition
10. Engine Oil Pressure
Low hot oil pressure can be caused by:
- Bearing wear
- Oil-pump wear
- Relief-valve fault
- Incorrect oil
Confirm with a mechanical gauge before dismantling.
11. Cooling System
Inspect:
- Radiator
- Water pump
- Fan/belt system
- Thermostat
- Coolant hoses
- Coolant concentration
12. Transmission Options
One of the most important differences between 40 Series tractors is transmission specification.
Depending on model and option package, tractors may use:
- Manual synchromesh arrangements
- Dual Command
- ElectroShift / powershift-type systems
- Shuttle or reverser arrangements
13. Identify the Transmission First
Before diagnosing a drive fault, confirm:
- Transmission type
- Number of ranges/gears
- Electrical controls
- Solenoid layout
- Pressure test points
14. Dual Command
Dual Command provides an additional hydraulically controlled ratio change.
Faults can involve:
- Low transmission pressure
- Solenoid fault
- Clutch-pack wear
- Electrical wiring
- Control switch
15. Powershift / ElectroShift-Type Systems
Where fitted, the transmission may use several hydraulic clutch packs controlled electronically.
Possible symptoms include:
- Missing gears
- Harsh shifts
- Slipping
- Delayed engagement
- Fault codes
16. Transmission Fault Codes
Electronic transmission faults may be caused by:
- Speed sensors
- Solenoids
- Clutch switches
- Wiring
- Low pressure
- Controller faults
A stored or active fault code can point toward the affected circuit and prevent unnecessary transmission strip-down.
17. Transmission Slips When Hot
Possible causes include:
- Internal clutch leakage
- Low hydraulic pressure
- Worn clutch packs
- Incorrect oil
- Weak pump
18. Clutch and Shuttle Controls
Depending on version, operator inputs may include:
- Mechanical clutch pedal
- Electronic clutch switch
- Shuttle lever
- Neutral/start interlocks
19. PTO System
Many tractors use an independent hydraulically controlled PTO.
Check:
- Engagement switch
- PTO solenoid
- Hydraulic pressure
- Speed sensor where fitted
- PTO clutch pack
20. PTO Will Not Engage
Possible causes include:
- Blown fuse
- Switch fault
- Solenoid fault
- Low hydraulic pressure
- Interlock fault
- Internal clutch wear
21. PTO Stops Under Load
Possible causes include:
- Clutch-pack wear
- Low pressure
- Control-valve leakage
- Electrical disengagement command
22. EDC – Electronic Draft Control
Many 40 Series tractors use electronic draft and linkage control.
EDC may control:
- Linkage raise/lower
- Position control
- Draft response
- External fender controls
23. EDC Fault Symptoms
Possible symptoms include:
- Linkage will not raise
- Linkage will not lower
- Erratic movement
- Warning lamp or fault code
- External controls not working
24. EDC Sensors
Depending on system, inputs may include:
- Position sensor
- Draft/load sensors
- Raise/lower switch
- External control switches
25. Linkage Will Not Raise
Check:
- Hydraulic oil level
- EDC fault codes
- Position sensor
- Solenoid valves
- Main hydraulic pressure
- Internal cylinder leakage
26. Linkage Drops or Hunts
Possible causes include:
- Position-sensor fault
- Internal leakage
- Control-valve leakage
- Calibration problem
27. Hydraulic System
Hydraulics may power:
- Three-point linkage
- Remote valves
- Steering
- Transmission/PTO control circuits
Exact circuit layout varies by tractor.
28. Weak Hydraulics When Hot
Possible causes include:
- Pump wear
- Internal leakage
- Relief-valve leakage
- Incorrect oil
- Filter restriction
29. Remote Valves
Check:
- Quick couplers
- Spool operation
- Flow control where fitted
- Detent function
- Internal leakage
30. Steering
Hydrostatic steering is common.
Weak steering can be caused by:
- Low oil
- Pump or priority-valve fault
- Steering-unit leakage
- Steering-cylinder leakage
31. Front Axle and 4WD
On four-wheel-drive tractors, inspect:
- Front axle oil
- Hub oil where separate
- Prop shaft
- Universal joints
- 4WD clutch/control
- Tyre matching
32. 4WD Will Not Engage
Possible causes include:
- Switch fault
- Solenoid fault
- Wiring issue
- Hydraulic clutch fault
- Mechanical driveline problem
33. Differential Lock
Depending on model, differential lock may use electro-hydraulic control.
Check:
- Switch
- Solenoid
- Hydraulic pressure
- Pedal/brake interlocks
- Internal clutch condition
34. Brakes
Wet-disc brakes are common on tractors of this type.
Symptoms to investigate include:
- Poor braking
- Pedal imbalance
- Brake drag
- Noise or chatter
- Contaminated oil
35. Electrical System
These tractors have considerably more electrical equipment than earlier classics.
Common faults include:
- Poor earths
- Corroded connectors
- Failed relays
- Sensor faults
- Broken wiring near cab pivots/controls
36. Charging and Starting
Check:
- Battery voltage
- Cranking voltage drop
- Alternator output
- Starter cable condition
- Cab and chassis earths
37. Cab Electrical Problems
Possible issues include:
- Instrument faults
- Heater/fan failure
- Lighting problems
- Wiper faults
- Control-switch failures
38. Fault Codes and Diagnostic Strategy
When a warning light or code appears:
- Record the exact code.
- Note whether it is active or stored.
- Check battery voltage.
- Inspect related connectors and wiring.
- Use the workshop manual test sequence.
- Clear codes only after repair.
39. Long-Storage Problems
- Stuck clutch or shuttle controls
- Water-contaminated oil
- Brake drag
- Corroded electrical connectors
- Fuel contamination
- Perished hoses
- Sensor faults from corrosion
40. Buying a 40 Series Tractor
Check:
- Exact model and transmission
- Cold starting
- Oil pressure and blow-by
- All transmission ratios
- PTO operation
- EDC linkage operation
- Remote hydraulics
- 4WD and diff lock
- Brake performance
- Dashboard warning lights/fault codes
41. Restoration and Repair Priorities
- Identify exact tractor and transmission.
- Read existing fault codes.
- Make engine and cooling system reliable.
- Service transmission/hydraulic oil and filters.
- Repair transmission/PTO controls.
- Repair EDC hydraulics and sensors.
- Repair steering, 4WD and brakes.
- Tidy wiring and cab controls.
- Finish with cosmetic work.
42. Workshop Checklist
| System | Check |
|---|---|
| Identification | Exact model, serial range and transmission confirmed. |
| Engine | Cold start, smoke, oil pressure and blow-by. |
| Transmission | All ranges/gears operate; codes checked. |
| PTO | Engages and holds under load. |
| EDC linkage | Raises, lowers and calibrates correctly. |
| Hydraulics | Remotes and steering strong when hot. |
| 4WD/diff lock | Electrical/hydraulic control operates correctly. |
| Brakes | Balanced and effective. |
| Electrical | Battery, charging, earths and connectors sound. |
Related Agrimanual Manuals
- Search Agrimanual 5640 manuals
- Search Agrimanual 6640 manuals
- Search Agrimanual 7740 manuals
- Search Agrimanual 7840 manuals
- Search Agrimanual 8240 / 8340 manuals
- Request a Ford / New Holland 40 Series manual
Frequently Asked Questions
Are all Ford / New Holland 40 Series tractors fitted with the same transmission?
No. Transmission specifications vary considerably. Identify the exact gearbox before diagnosing codes, pressures or clutch-pack faults.
Why will the EDC linkage not raise?
Check fault codes, position/draft sensors, solenoids, hydraulic pressure, oil level and internal leakage before replacing the controller.
Why does one transmission ratio disappear?
Depending on the transmission, a failed solenoid, wiring fault, low clutch pressure or worn clutch pack can remove one ratio or group of ratios.
Can low battery voltage cause strange fault codes?
Yes. Electronic transmission and EDC systems can produce multiple misleading faults when supply voltage or earth connections are poor.
Why do hydraulics and steering become weak when hot?
A common supply or pump problem may be present. Check oil, filters, pressure, flow and internal leakage using the correct manual.
The Ford / New Holland 40 Series sits at an interesting point between traditional mechanical tractors and modern electronically controlled machines. They remain very repairable, but accurate diagnosis of transmission, EDC and electrical faults is far better than replacing parts by guesswork.