Semi Truck Transmission Trouble: Recognizing Early Signs

Posted on: 1 January 2018

When you drive a semi-truck for a living, it's important that you're attentive to any potential signs of trouble. After all, a malfunction such as a failed transmission on the road can be dangerous for you and for others on the road. Not to mention, it will lead to costly repairs and down time. The best thing you can do is familiarize yourself with the early warning signs of semi-truck transmission trouble. That way, you can have issues addressed before they become disastrous.

Leaking Fluid

You should check your transmission fluid on a regular basis to ensure that it's at the proper level. Low fluid indicates that there's a leak somewhere, which is dangerous. If the fluid gets too low, the transmission could seize.

Look for signs of a fluid leak below the transmission and around all of the lines that run from it. While you're at it, look at the condition of the transmission fluid, too. It should be clean, red, and the proper viscosity. If it's dark, full of any kind of debris, cloudy, or thick, that's another indication of a problem that should be addressed right away.

Transmission Noises

Your transmission shouldn't make any kind of squeal or grating noise at all, so if you're hearing something like this, it should be cause for concern. When the noise occurs is a key part of determining what could be the problem.

For example, if you hear it when you depress the clutch, that's an indication that the clutch release bearing may be failing. However, if you're only hearing those things when the truck is idling and you haven't depressed the clutch, it may mean that the clutch disc or the torque tube bearings are failing.

Shifting Hard

When you shift the transmission, it should be smooth and nearly effortless. If your transmission is shifting hard or bucking, that could be an indication of sensor failure. Whether it's a shift sensor or an oxygen sensor, you'll need to have them all tested to find the source of the issue. Once you replace the faulty sensor, it should restore your transmission's handling.

If your truck has an automatic transmission with a shift sensor, it may also be shifting too early or too late. If it's shifting too late, the engine RPMs will rev before the transmission picks up the next gear. If it's shifting too early, you may feel some lag in the truck when it shifts. If you don't have a shift sensor that's failing, these symptoms could also be the result of an improperly adjusted throttle cable. Contact a service shop, like Color Country Diesel Inc, for more help.