Troubleshooting and Repairing Transmission Problems in the 1998 IT28G Loader

[MikePhua]

The 1998 IT28G, an articulated wheel loader manufactured by New Holland, is a powerful machine used in a variety of industries, from construction to agriculture. Known for its efficiency, durability, and performance, the IT28G has long been a favorite among operators. However, like any complex piece of machinery, it can encounter issues, particularly with its transmission system, which is essential for transferring power from the engine to the wheels.
Transmission problems can be especially frustrating since they can severely limit the loader's performance. In this article, we’ll explore common transmission issues that operators face with the 1998 IT28G loader, how to diagnose them, and potential solutions to ensure that the loader continues running smoothly.
Understanding the Transmission System in the IT28G
The transmission in the IT28G is an integral part of the drivetrain, responsible for enabling the loader to shift gears and move efficiently. The system uses a combination of hydraulics and mechanical components, which require regular maintenance to prevent premature wear and failure.
For the 1998 IT28G loader, the transmission is a hydrostatic drive, which combines both hydraulic and mechanical power. This system allows for smooth operation under heavy loads and is designed to work in demanding environments. However, as with any mechanical system, problems can arise due to wear and tear, improper maintenance, or operational misuse.
Common Transmission Problems in the IT28G
Transmission issues can manifest in various ways, from slipping gears to strange noises or poor shifting performance. Below are some common problems that operators may experience with the IT28G loader’s transmission and their potential causes.

1. Transmission Slippage
   

One of the most common symptoms of a failing transmission is slippage, where the loader doesn’t respond as expected to throttle input, or it may struggle to maintain speed, especially under load.
Possible Causes:

• Low Hydraulic Fluid: Since the IT28G uses hydraulic power for its transmission, low hydraulic fluid can result in slippage. Hydraulic fluid is essential for maintaining the correct pressure within the system.
  
• Worn Clutch Plates or Bands: Over time, the clutch plates or transmission bands can wear down, leading to improper gear engagement and slippage.
  
• Faulty Torque Converter: The torque converter regulates the connection between the engine and the transmission. If it fails or becomes damaged, it can lead to power loss and slippage.
  

Solutions:

• Check Hydraulic Fluid Levels: The first step is to check the hydraulic fluid levels and condition. If the fluid is low or dirty, replacing it with the recommended fluid can often solve the issue. Always use the specified fluid type to ensure proper transmission function.
  
• Inspect Clutch Plates and Bands: If fluid levels are correct but the slippage continues, inspect the clutch plates and bands for wear. These components may need to be replaced if they are worn or damaged.
  
• Torque Converter Diagnosis: If slippage persists, the torque converter should be inspected. A mechanic may need to perform a pressure test or dismantle the transmission to assess the converter's condition.
  

1. Delayed or Harsh Shifting
   

Delayed or harsh shifting occurs when the loader has trouble shifting gears or when gear changes are not smooth. Operators may experience jerky movements or even complete failure to change gears.
Possible Causes:

• Contaminated Transmission Fluid: Dirty or contaminated fluid can cause poor shifting performance by clogging filters or restricting flow in the transmission system.
  
• Damaged Solenoid or Valve: The solenoid controls the flow of fluid to the transmission’s shift valves. If a solenoid malfunctions, it can delay or prevent proper shifting.
  
• Faulty Shift Linkage: If the shift linkage is out of adjustment, it can cause improper gear engagement, leading to harsh or delayed shifts.
  

Solutions:

• Fluid Flush and Filter Change: A fluid flush and replacement of the transmission filter is often the first step in addressing shifting issues. Regular fluid changes are essential for smooth operation.
  
• Inspect Solenoids and Valves: Solenoids and shift valves should be checked for wear or electrical failure. A diagnostic scan tool may be required to check for fault codes related to the transmission system.
  
• Adjust Shift Linkage: The shift linkage should be adjusted to ensure smooth and consistent gear changes. If the linkage is worn or damaged, replacement may be necessary.
  

1. Transmission Overheating
   

Another common issue with transmissions in heavy machinery like the IT28G is overheating. Excessive heat can cause damage to internal components, leading to premature failure.
Possible Causes:

• Low or Contaminated Fluid: Low fluid levels or old, contaminated fluid can reduce the cooling effect, causing the transmission to overheat.
  
• Blocked or Dirty Radiator: The transmission cooler is typically part of the loader’s radiator system. If the radiator becomes clogged with dirt, debris, or oil, the transmission can overheat.
  
• Heavy Usage or High Loads: Prolonged use under heavy loads, especially on hot days, can also contribute to transmission overheating.
  

Solutions:

• Check Fluid Levels and Condition: Ensure that the fluid is at the proper level and in good condition. Change the fluid if it’s contaminated or degraded.
  
• Clean the Radiator: Inspect the transmission cooler and radiator for dirt, debris, or oil buildup. Clean the cooling system to ensure proper heat dissipation.
  
• Reduce Heavy Load Usage: Try to limit the amount of time the loader is operated under heavy loads, especially in extreme heat, to reduce the risk of overheating. Taking periodic breaks can help cool the transmission system.
  

1. Strange Noises from the Transmission
   

Unusual noises, such as grinding, whining, or clunking sounds, coming from the transmission can indicate serious issues, including gear damage or lack of lubrication.
Possible Causes:

• Worn or Broken Gears: Internal gear damage, often caused by lack of proper lubrication or excessive stress on the transmission, can lead to grinding or whining sounds.
  
• Damaged Bearings: Bearings within the transmission can wear out over time, especially if the loader is used for heavy-duty work or under harsh conditions.
  
• Low or Old Fluid: Insufficient lubrication can cause internal components to rub together, leading to unusual noises.
  

Solutions:

• Inspect Gears and Bearings: If strange noises persist, the transmission should be inspected for damaged gears or bearings. A full teardown may be necessary to assess the damage and replace faulty components.
  
• Fluid Inspection and Change: Ensure that the transmission fluid is clean and at the correct level. If the fluid is old, a complete fluid change may solve the noise issue.
  

Real-World Example: A Case of Transmission Slippage
A construction company working with an IT28G loader in a rocky, hilly environment started noticing transmission slippage. Despite ensuring the hydraulic fluid was at the correct level, the loader would lose power on steeper inclines. Upon further inspection, the clutch plates and bands showed significant wear, likely caused by extended use without proper maintenance. After replacing the worn components and flushing the transmission system, the loader’s performance was restored, avoiding potential damage to the drivetrain.
Conclusion: Timely Maintenance is Crucial
Transmission problems in the 1998 IT28G loader can cause major disruptions in productivity, leading to costly downtime and repairs. However, many of these issues can be avoided with proper maintenance, including regular fluid checks, timely component replacements, and frequent inspections. By diagnosing and addressing transmission problems early, operators can ensure that their IT28G loader continues to perform reliably and efficiently for years to come.
Whether dealing with slippage, overheating, or unusual noises, following the manufacturer’s recommended service intervals and using quality fluids will keep your loader in optimal condition, saving you time and money in the long run.