John Deere 455G Second Gear Issues and Transmission Behavior

[MikePhua]

The 455G and Deere’s Evolution in Crawler Loaders
The John Deere 455G crawler loader was introduced in the late 1980s as part of Deere’s G-series, succeeding the 455D and continuing the legacy of mid-size track loaders built for grading, loading, and land clearing. With an operating weight around 16,000 pounds and a 70-horsepower diesel engine, the 455G was designed for versatility in construction and agricultural settings. It featured hydrostatic steering, a torque converter transmission, and a mechanical shuttle system that allowed directional changes without clutching.
John Deere’s crawler loader lineage dates back to the 1950s, and the 455 series became one of its most successful platforms, with thousands of units sold across North America. The G-series refined operator comfort, hydraulic response, and drivetrain durability, but like many machines of its era, it occasionally presented quirks—especially in gear selection and shifting behavior.
Understanding the Transmission Layout
The 455G uses a powershift transmission with a torque converter and planetary gear sets. It offers four forward speeds and four reverse speeds, selectable via a shift lever mounted near the operator’s right hand. The transmission is hydraulically actuated, with clutch packs engaging specific gear sets based on lever position.
Key terminology:

• Torque converter: A fluid coupling that multiplies engine torque and allows smooth engagement.
  
• Planetary gear set: A compact gear system that provides multiple ratios in a small space.
  
• Clutch pack: A series of friction discs and steel plates that engage or disengage gear sets.
  
• Modulating valve: A hydraulic valve that controls clutch engagement pressure for smooth shifting.
  

One operator in Oregon described how his 455G would hesitate when shifting into second gear, especially under load. After inspection, the issue was traced to a worn modulating valve spring that caused delayed clutch engagement.
Second Gear Hesitation and Diagnostic Pathways
Second gear issues in the 455G often manifest as:

• Delay or hesitation when shifting from first to second
  
• Engine revs increase but machine does not accelerate
  
• Jerky engagement or sudden lurching
  
• Gear fails to engage under load but works when unloaded
  
• Transmission overheats during prolonged second gear use
  

Diagnostic checklist:

• Check transmission fluid level and condition
  
• Inspect shift linkage for wear or misalignment
  
• Test clutch pack pressure using hydraulic gauges
  
• Examine modulating valve for spring tension and spool wear
  
• Inspect filter and suction screen for debris or restriction
  

Recommendations:

• Use John Deere Hy-Gard or equivalent transmission fluid with correct viscosity
  
• Replace modulating valve springs if engagement is inconsistent
  
• Clean or replace suction screen to restore hydraulic flow
  
• Adjust shift linkage to ensure full detent engagement
  
• Monitor transmission temperature during operation—should remain below 200°F
  

One technician in Georgia found that a clogged suction screen caused low clutch pressure in second gear. After cleaning the screen and replacing the fluid, the gear engaged smoothly even under full bucket load.
Wear Patterns and Preventive Maintenance
Second gear is often used during moderate-speed travel and light loading, making it susceptible to wear from partial engagement or low hydraulic pressure. Over time, clutch packs can glaze or lose friction material, especially if fluid is contaminated or overheated.
Preventive strategies:

• Change transmission fluid every 500 hours or annually
  
• Replace filters at each fluid change
  
• Inspect shift linkage bushings and detents quarterly
  
• Use infrared thermometer to monitor case temperature
  
• Avoid prolonged idling in gear—return to neutral when stationary
  

One fleet in Alberta implemented a fluid sampling program for their crawler loaders. By analyzing transmission oil every 250 hours, they identified early signs of clutch wear and scheduled service before failure occurred.
Field Solutions and Operator Techniques
In remote or time-sensitive situations, operators have developed workarounds to manage second gear issues.
Field tips:

• Shift into second gear while rolling to reduce load on clutch pack
  
• Use first gear for heavy pushing and skip directly to third for travel
  
• Feather throttle during engagement to reduce shock load
  
• Avoid shifting under full hydraulic load—lift bucket before gear change
  
• If gear fails to engage, return to neutral and retry with slight throttle
  

One contractor in Texas trained his operators to shift into second gear only after reaching 1,200 RPM in first. The technique reduced clutch chatter and extended transmission life across the fleet.
Conclusion
Second gear hesitation in the John Deere 455G is often a symptom of hydraulic imbalance, clutch wear, or linkage misalignment. By understanding the transmission’s internal logic and maintaining fluid integrity, operators and technicians can restore smooth engagement and prevent long-term damage. In the world of crawler loaders, every gear matters—and second gear, often overlooked, plays a pivotal role in productivity and drivability.