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In the United States, an 18-wheeler can weigh up to 80,000 pounds when fully loaded and gassed up – almost 32 times the average weight of a hatchback. As a truck operator, you know that a responsive engine is essential to controlling a vehicle of this size, especially in challenging road conditions.

In many situations, your semi’s clutch plays an instrumental part in keeping your truck efficient, functional, and on the road. However, because your clutch sees so much action, this component can wear out over time.

Heavy-duty clutches of the type used in 18-wheelers last longer than those used in smaller vehicles, but automotive experts report that these components usually wear out by the time they reach 50,000 miles. Understanding how a truck mechanic might approach clutch repairs can help prepare you for the day that you realize your clutch needs an upgrade. In this blog, we discuss the fundamentals of semi-truck clutch rebuilding.

When should you consider rebuilding?

Signs of clutch problems can be subtle initially but often become obvious quickly. Common symptoms of a damaged or worn out clutch include:

  1. Burnt smell during clutch use
  2. Difficult clutch disengagement
  3. Excess engine revving while the clutch is engaged
  4. Resistant or entirely un-resistant clutch pedal
  5. Slowed acceleration
  6. Too-fast clutch disengagement
  7. Unusual noise when shifting


When you notice warning signs that point to a problem with your clutch, have a mechanic evaluate your engine to ensure that the issue really is with the clutch and not another component, like the transmission.

How Does the Clutch Rebuilding Process Work?

During clutch rebuilding, the mechanic removes the entire clutch apparatus from the semi and assesses which parts have sustained damage or become obstructed due to debris buildup. The mechanic then works on each of these parts to restore them.

Once each part is returned to full functionality, the mechanic then puts the clutch back together and reinstalls it in the semi.

What Is the Difference Between Rebuilding and Remanufacturing?

Many truck operators use the terms rebuilt and remanufactured interchangeably. However, while these processes are similar, they are not the same in terms of product or price. As discussed in the previous section, rebuilding involves repairing individual parts and then reassembling the clutch.

During remanufacturing, each component is ordered or is sent to a machining department to be remade. These new and like-new parts are then reassembled into a clutch. Remanufactured parts can cost as much as replacement clutches and may include components that are not the same as OEM parts.

What Is the Difference Between Adjustment and Rebuilding?

In some cases, a faulty clutch may not need a full rebuild. Instead, the mechanic may be able to make the necessary repairs without removing the entire clutch from the truck. You will likely need the perspective of an experienced mechanic to determine which exact clutch service is necessary.

Why Should You Rebuild Rather Than Replace?

When your clutch goes out, you have two main options: rebuild or replace. Many truck operators assume that replacement offers them a higher quality, and therefore safer, part and a faster turnaround time.

However, many mechanics report that, in most cases, a clutch can be adjusted and/or rebuilt multiple times before it requires full replacement. The rebuilding process is significantly more affordable than replacement. Your mechanic can provide you with an estimate of how long the rebuild will take and the time period is typically shorter than you think.

If you notice any signs of clutch slippage, wear, or failure, have the component assessed by an experienced semi-truck mechanic. Use your mechanic’s recommendations, as well as the information above to decide whether rebuilding your clutch is the right choice in your situation.

For comprehensive 18-wheeler work, including clutch rebuilding, trust the expert team at S&T Truck Repair.