Signs Of Worn Drivetrain Components In Heavy-Duty Trucks And How To Repair Them

General Truck Repair
Signs Of Worn Drivetrain Components In Heavy-Duty Trucks

Your drivetrain plays an important role in allowing the wheels on your heavy-duty truck to turn. Like all other parts of your vehicle, they can face a range of problems. In this article, we will dive into drivetrain components, how to identify issues, and what repairs are needed to resolve them. 

Drivetrain Components 

Transmission: Controls power and torque generated by the engine as well as changing gears and adjusting the speed of the truck based on road conditions and load requirements. 

Driveshaft: This is a long cylindrical shaft with universal (U) joints at each end that connects the transmission to the rear axle and transfers rotational power from the engine. 

Differential: These are a set of gears locked in the axle that distribute power and allow the wheels to spin at different speeds while making a turn.

Axles: These transfer power from the driveshaft to the wheels and support the weight of the truck and cargo. 

Transfer case: If your truck is four-wheel drive, the transfer case diverts power to both the front and rear axles for better traction and off-road capabilities. 

Signs of Worn Driveshaft Components 

There are many signs to be on the lookout for to determine if your heavy-duty truck is experiencing driveshaft issues, including: 

Unusual Noises 

A telltale sign of driveshaft issues is strange noises from under your truck. Different noises can help you identify the potential issue.

  • Whining or grinding noises: Worn-out differential or transmission bearing 
  • Clunking during gear changes: Worn or failing U-joints
  • Squeaking: U-joints or bearings need lubrication 
  • Rattling or grinding sounds: Worn or unlubricated driveshaft components

Excessive Vibrations 

Although your truck will naturally vibrate regardless of its condition, excessive vibrations coming from below the truck could indicate U-joints or driveshaft bushings beginning to wear. 

If you notice shudders when accelerating from a stop or low speed, this could be down to a loose U-joint or a bad carrier bearing.

Difficulty Shifting Gears 

Difficulty shifting or a delayed response could indicate problems within the transmission system. Typically, this will result from low transmission fluid, worn synchronizers, or clutch issues. 

Slipping gears can make you lose control of your vehicle, endangering you and other drivers on the road. A worn-out clutch, broken bands, or insufficient fluid levels are typically to blame for this. 

Leaking Fluids

Puddles or spots beneath the truck can be due to various problems, such as loose bolts or holes in your transmission. If it’s coming from the differential, then this could be due to a leaking gasket, a leaking pinion seal, or a leaking differential side seal. 


Excessive heat in the transmission or differential can lead to serious damage, and steps must be taken to combat this. Ways of identifying internal leaks include burning smells, hot surfaces, and dashboard warning lights. 

Increased Fuel Consumption 

Increased energy losses, reduced fuel efficiency, and a significant decrease in fuel economy could signal drivetrain problems. 

Visible Wear and Tear 

Worn-out gears, cracked U-joints, damaged axles, and most obviously, any signs of rust and corrosion on components, especially the bearing cap seals.

Excessive U-Joint Play 

Shifting the U-joint yokes back and forth after putting the truck into park or neutral and noticing that there is too much play is a sign your driveshaft needs attention. 

Difficulty Turning 

This could be a U-joint issue, as failing U-joints prevent the wheels from turning properly, resulting in poor control and potentially becoming a hazard on the road. 

Causes of Drivetrain Issues

There are numerous different reasons why your drivetrain may be failing; some are inevitable, while others can be easily addressed.

Excessive Loads 

Your truck will often carry substantial loads, which will inevitably put a strain on your drivetrain components. Frequent hauling of heavy cargo or overloading past the recommended weight can lead to accelerated component wear. 

Rough Driving Conditions 

Uneven terrain, off-road driving, and pot-holed roads place additional strain on your drivetrain, leading to faster wear and tear. 

Lack of Maintenance

Failing to change the transmission fluid, adequately lubricate components, or inspect U-joints can result in premature failure. This is why a comprehensive routine preventive maintenance schedule is important for optimizing the performance, longevity, and safety of your vehicle. 

Improper Lubrication 

Insufficient or contaminated lubrication will not perform as it should, which will increase friction between components, resulting in their rapid deterioration.

Driving Habits 

Hard accelerations, sudden braking, and rough gear changes put unnecessary strain on components, causing them to wear faster. 

Excessive Heat

Continuous driving in extreme temperatures can place additional strain on transmission and differential components, which can lead to accelerated wear and permanent damage. 

Contaminants and Debris 

Contaminants can infiltrate components, leading to abrasive wear and reduced performance. 

Age and Mileage 

It goes without saying that the older your truck is with more miles on the clock, then it is going to be more susceptible to component wear and potential failure than newer models. 

Manufacturer Defects 

Sometimes the manufacturer makes a mistake and sends out trucks with faulty parts. This happens more often than you think and usually results in a mass recall

Repairing Drivetrain Issues 

Each component requires different types of maintenance and repairs. Often, more complex issues will have to be handled by professionals like our team at Saviors Repair. 


Basic maintenance: Regularly check transmission fluid levels and condition. Top up and replace where necessary, following the manufacturer’s recommendations.
Advanced repairs:
Clutch replacement or transmission rebuilds handled by professional mechanics. 


Basic maintenance: Inspect for visible signs of damage or imbalance. Grease U-joints periodically to ensure smooth operation.
Advanced repairs:
If the driveshaft is damaged or severely imbalanced, large-scale repairs will be required. 


Basic maintenance: Check differential fluid levels and conditions regularly. If there are leaks and contaminants, address them immediately by replacing or repairing seals. 

Advanced repairs:
Repairing or rebuilding differentials is a complex, more advanced repair that will need to be left to the professionals. 


Basic maintenance: Inspect axles for visible signs of damage or wear. Ensure that the axle nuts are correctly torqued to prevent wheel bearing issues. 
Advanced repairs:
Replacing axles and fixing internal axle problems such as bearing failure, a damaged axle shaft, and axle seal leaks. 

Final Thoughts 

Drivetrains are complex pieces of equipment made up of a range of different components, each with its own issues that they can suffer from. Although some measures can be put in place to prevent premature wear and failure, sometimes repairs are needed. 

In this case, it is best to leave these up to professional mechanics like our skilled team at Saviors Repair, where we offer a comprehensive drivetrain repair service to get you back on the road in no time. 

Contact Saviors Repair Today!

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