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The Most Common Reasons for Transmission Issues in Semitrucks (and How to Prevent Them)

Category: Equipment and Solutions

The transmission is a crucial component of any semi. When it starts to suffer, it usually gives off some warning signs. By knowing what to look for and how to keep your diesel truck’s transmission in good shape, you can avoid costly transmission problems.

Common Semitruck Transmission Problems

Here are some of the most common diesel engine transmission issues and what you can do to prevent them.

1. Issues With Switching and Staying in Gear

Low transmission fluid might be to blame if you have problems with:

  • Gears not engaging.
  • Not staying in gear.
  • Taking a long time to get into gear.
  • Transmission slips.
  • High engine revving.

You might have low transmission fluid due to leaks, contamination or problems with the shifter, shifter cable or valve body of an automatic transmission. In addition to the above issues, these problems can cause overheating or a burning smell if a leak burns on hot components. Check your dipstick levels for low fluid. You can also look underneath the vehicle for red fluid indicating a leak.

2. Noises

Noises like buzzing, clunking, humming or grinding can indicate internal problems, like bad seals or low transmission fluid. A grinding sound while shifting can indicate that the clutch is not releasing or that there’s wear and tear on components like the shifter, synchronizer rings or the gears themselves.

3. A Low- or High-Grabbing Clutch Pedal

A clutch pedal that grabs very high may indicate an adjustment issue or worn components, such as the pressure plate or clutch disc. If the pedal grabs very low, the problem might lie with the hydraulic system.

4. Transmission Slips or High Revving

These problems are often the result of low transmission fluid and contamination. Other culprits include poor maintenance and worn-down parts.

5. No Power

If the engine is running but the vehicle isn’t receiving power, the computer might be limiting power because it detects an engine problem. Another possible source is dragging brakes. Look for trouble codes to point you in the right direction.

Preventing Semitruck Transmission Problems

The best way to mitigate transmission problems for semitrucks is to stick to comprehensive preventive maintenance practices and avoid activities that stress the transmission. Consider these prevention tactics:

  • Take care of your transmission fluid: Regularly check fluid levels and don’t overfill. Review the manual to be sure you’re using the right kind of transmission fluid for the vehicle.
  • Avoid overheating the transmission: Monitor heat levels and avoid overloading the vehicle. If needed, install an auxiliary cooler and give the vehicle plenty of time to warm up on cold days.
  • Don’t be hard on the transmission: Don’t make high-performance starts or spin tires unnecessarily. Always use the emergency brake when parked on an incline to reduce component stress. If you get stuck and need to rock between gears, be gentle and allow the wheels to stop before switching gears.
  • Conduct regular inspections: Make sure an expert inspects the semitruck regularly and performs maintenance as needed.

Transmission Service in Nebraska

If you spot a transmission problem or suspect one, acting quickly can help you avoid more damage. NMC Cat Truck Centers are situated across Nebraska, in Omaha, Scottsbluff, Norfolk, Doniphan, Lincoln and North Platte. Each location has advanced diagnostic equipment and the expertise needed to identify specific issues and offer prevention services for diesel transmissions. We can conduct a wide range of repairs and have replacement parts such as pumps, planetary gear sets and hydraulic systems in stock.

Reach out to us online or at 402.542.5352 to talk to a representative.