Lull 1044C-54 Series II Telehandler Detailed Overview

[MikePhua]

Machine Description and History
The Lull 1044C-54 is a heavy-duty telehandler produced by JLG Industries under the Lull brand. The model was first introduced around 1996. A major revision (Series II) occurred in about 2005 when the engine was changed from a Cummins powerplant to a John Deere 4045TF model.
Lull machines (via JLG) are known for combining reach, lift capacity, and specialized features like the “Transaction Boom” (which allows forward horizontal movement of the boom without repositioning the whole machine) to improve load placement flexibility.  These telehandlers are used widely in construction, materials handling, and rental fleets, especially in North America.

Technical Specifications
Here are key specifications for the 1044C-54 Series II:

• Engine: John Deere 4045TF, 4-cylinder, 4.5 L displacement, rated at ≈ 115 hp (≈ 85 kW) at 2,500 rpm.
  
• Operating Weight: ~32,700 lb (≈ 14,900 kg) with a 50-in carriage and forks.
  
• Rated Capacity: 10,000 lb (≈ 4,536 kg).
  
• Maximum Lift Height: 54 ft (≈ 16.5 m).
  
• Max Travel Speed: ~22 mph (≈ 35 km/h).
  
• Hydraulics: Dual load-sensing gear pumps; full hydraulic system capacity ≈ 33.5 gal (≈ 127 L).
  
• Transmission: Power shift with 4 forward speeds, 3 reverse speeds.
  
• Other features:
  • Outriggers that pivot off the front axle for frame leveling.
    
  • Pilot-operated joystick controls for boom, frame leveling, auxiliary functions.
    
  • Various carriage and fork attachments, swing carriage options.
    

Common Issues & Failure Modes
Based on reports from operators, mechanics, and forum cases, several recurring problems emerge in the 1044C-54 Series II. These include:
Engine Shutoff / Intermittent Stalling

• After 10-20 minutes of operation, the engine sometimes shuts off unexpectedly.
  
• Restarting requires waiting a bit or cycling the key. No obvious warning codes visible without diagnostics.
  
• Potential causes include a faulty temperature sensor, or a failing shut-off solenoid.
  

White Smoke at Startup / Rough Warm-up

• After sitting for some time, on cold start the machine emits significant white smoke, and runs roughly until warmed up.
  
• Possible origin: one cylinder with compromised sealing (e.g. a previously bent rod or cylinder work) or head gasket issues.
  

Electrical Flicker, Loss of Control Circuits

• On a 2004/2005 unit, control board lights may flicker after running for a minute or so; during flicker, some functions (boom out, drive / forward-reverse) fail.
  
• No clear error codes in older models; suggests wiring, connector corrosion, loose grounds, or failure in PC/control board itself.
  

Cold Weather Hydraulic Hardness

• In cold temperatures (≈ 10-25°F / -12 to -3 °C), hydraulic functions are sluggish — frame tilt especially slow.
  
• System seems to struggle until warmed. Fluid has been changed, accumulator was charged. System pressure readings show erratic behavior: one pump shows pressure, the other shows zero except when lever is engaged, then drops.
  

Proximity/Limit Switch Sensor Problems

• Boom extension may be refused when both proximity sensors are “in”; removing one sensor plug may allow extension but disable travel or drive. An “OSC lock” (oscillation lock) light may come on.
  

Terminology & Technical Notes

• Shut-off solenoid: a device that stops fuel flow or ignition when engine needs to stop; failure can cause unexpected shutdown.
  
• Pilot pressure: small hydraulic pressure used to actuate main control valves; if pilot pressure is low, main functions won’t work.
  
• Accumulator: hydraulic device storing pressurized fluid (often with gas precharge), to dampen pressure spikes or maintain functions under load.
  
• Proximity sensor / limit switch: small sensors that detect positions (e.g. boom position, outriggers, frame position) and often signal the control logic to permit or prevent actions.
  

Troubleshooting & Repair Suggestions
To address these issues, operators & technicians should follow a systematic diagnostic approach. Here are suggestions:

1. Inspect & retrieve fault codes (if ECM/ECU / control module present). Even older models may have hidden blink codes via switches or sensor override switches.
   
2. Engine Stoppage / Rough Warm-up
   • Check the shut-off solenoid for sticking or failing.
     
   • Inspect temperature sensors (coolant temp, oil temp) and wiring; see if readings are correct under diagnostics.
     
   • Examine cylinder(s) with known damage—check for compression, leaks, gaskets.
     
3. Electrical System & Control Board
   • Check battery condition (cold cranking amps, age), alternator output.
     
   • Inspect ground straps, bulkhead connectors, harness connectors—look for corrosion, looseness, damaged wiring.
     
   • Observe voltage stability with key on / machine running.
     
4. Hydraulic System & Cold Weather Behavior
   • Use hydraulic fluid rated for cold ambient conditions. Thicker oil can severely reduce flow or delay spool shifting.
     
   • Check pilot pressure – measure with the function lever activated; ensure minimum required pilot pressure is met.
     
   • Verify accumulator pre-charge (gas side) is correct.
     
   • Inspect hydraulic filters, especially those in pilot circuit, for clogging or water.
     
5. Proximity Sensor / Limit Switch Problems
   • Identify all sensors involved with boom extension OEM-spec. Check whether replacement sensors are normally open (NO) or normally closed (NC); mixing types can cause logic errors.
     
   • Test each sensor independently. Check continuity, signal integrity, wiring.
     
   • Check for stuck or falsely triggered sensors under vibration or movement.
     
6. Preventive Maintenance
   • Regular cleaning and lubrication of connectors and pins.
     
   • Ensuring warm-up routines in cold weather: idle the machine to warm engine and hydraulic oil before full load.
     
   • Replace fluids and filters at recommended intervals; monitor for water contamination.
     

Real-World Cases & Anecdotes

• One user described a 2008 1044C-54 whose engine would shut down after ~20 minutes, with check engine light illuminated. They suspected temperature sensors or shut-off solenoid. Upon investigation, the issue turned out to be a loose connection to the shut-off solenoid along with a marginal coolant temperature sensor reading causing the ECM to force shutdown.
  
• Another operator in cold climate noted that the frame-tilt behavior was nearly non-existent until oil warmed. They changed to a winter-grade hydraulic oil, recharged the accumulator properly, and replaced a pilot-circuit filter; performance improved markedly after those steps.
  
• In a case of boom non-extension, replacement of a proximity sensor was done; but after replacement, the OSC lock engaged, and the machine wouldn’t drive. The sensor’s electrical characteristics (NO vs NC) were mismatched to the logic input, causing the control logic to interpret a “limit reached” condition continuously. Swapping in the correct type resolved the issue.
  

Data & Figures to Aid Diagnosis
Here are useful reference measurements / thresholds often encountered:

• Pilot pressure requirement: often several hundred psi (depending on brand) — e.g. in one case ≈ 500 psi minimum.
  
• Hydraulic fluid system capacity: ~127 liters.
  
• Engine rated speed: 2,500 rpm. At low pilot pressure and cold oil, pressures may read zero under idle.
  
• Operating temperature thresholds: cold behavior noted below ~10-25°F (≈ -12 to -3 °C).
  

Conclusion
The Lull 1044C-54 Series II telehandler is a capable and widely used machine, but its complexity in hydraulics, sensors, and electrical control combined with environmental stresses (cold, vibration) can produce recurring issues: unexpected engine shut-downs, loss of function, electrical flicker, boom / drive safety interlocks. Many of the problems share a common root in failing sensors, worn or corroded electrical connections, weak pilot pressure (especially when cold), and mismatched sensor logic.
By methodical diagnosis—checking sensors, wiring, pilot pressure, hydraulic filter clean‐liness, accumulator charge—and ensuring correct components (sensors of right type, proper fluid, correct thresholds), most of the common faults can be resolved. Operators working in cold climates should give the machine time to warm up, use fluids rated for those temperatures, and regularly inspect vulnerable connectors and switches.