The U-joint on your off-road truck is a part that doesn't get a lot of attention, at least until it breaks. This essential part of your drivetrain makes the transfer of power from transmission to wheels possible. Without it, you will be going anywhere soon.
U-joints on off-road trucks take a lot of abuse and can break if not properly maintained. To avoid this problem and ensure you always have the power needed for hill climbing, read below and learn how to take care of the u-joint.
What Does the U-Joint Do?
Universal or u-joints are flexible, pivoting devices that connect the drive shaft to the axles on vehicles like off-roading trucks with heavy duty bumpers. The drive shaft takes power from the transmission to the drive axle, which transfers that power to the wheels. The purpose of the u-joint is to compensate for movement of the drivetrain under the vehicle so the drive shaft is not damaged.
This joint is composed of the end of the drive shaft, the end of the drive axle, and a cross-shaped part that joins them together. The cross makes the drive axle rotate with the drive shaft, even if the drive shaft is moving under the vehicle due to strain from the suspension. Although the actual joint includes all three parts, the cross piece itself is generally considered to be the u-joint.
Following are the ways to properly maintain and protect the u-joint on your off-road truck:
- U-Joint Size and Rating - A U-Joint is only as strong as the cross piece, which is designed to handle various amounts of torque. The first and most important way to protect a u-joint is to have one strong enough for your truck. Bigger axles, higher horsepower, heavier tires, and heavy duty bumpers all put more strain on the u-joint, increasing the chance that it will break if not durable enough. A stock u-joint that comes on a regular vehicle is not designed for trucks with heavy duty bumpers used for off-roading. To protect any u-joint, you must know its load rate and decide whether you need to replace it with a larger joint rated for higher torque.
- C-Clips and Snap Rings - At the four ends of the u-joint, there are c-clips or snap rings set into the caps that protect the u-joint. If one falls off, the yoke can move sideways in the joint. When this happens, the u-joint may become loose and noisy; it could break after a while. Prevent this by frequently checking to make sure all c-clips or snap rings are there and securely seated in the cap. If you hear a clunking noise while your off-roader is moving or put in reverse, you probably have a missing c-clip.
- Greasing - U-joints can be sealed or unsealed. The sealed and non-greasable u-joints that come standard on many vehicles are not recommended for off-roading as they can easily be contaminated by dirt. Dirt in a sealed u-joint will cause unnecessary wear, shortening its lifespan. Unsealed u-joints require occasional greasing and can be taken apart for cleaning as needed.
Although u-joints are important, it really does not take much to maintain them. Check your vehicle's c-clips during regular maintenance, keep the joint well greased; and consider upgrading to a bigger one designed for trucks with steel bumpers, huge tires, and bigger axles.
Beyond this, check often for play in the joint and pay attention to any sounds under your truck. If you suspect a problem with your u-joint, look into it before it breaks and leaves you and your off-road truck stranded!