4 Symptoms of a Faulty Push Fork
Everyone wants to focus on the engine and transmission, but there’s more to it than that if you want your car to function properly. One of the most important components that transfers power from the engine and transmission to the wheels is the driveshaft.
The driveshaft has many components that contribute to its proper functioning, including the thrust fork. When it’s working properly, it does a great job of keeping everything running smoothly, but when it’s not working properly, it can cause all kinds of problems. But how do you know if your push forks are faulty? Read on to learn about signs of a defect and whether repair or replacement is the solution.
What is a slip fork? Before we delve into identifying a faulty slip fork, we need to know what a slip fork is. The simple answer is that it is a part of the driveshaft. The longer answer is that it is both a type of driveshaft and the internal splines that connect the driveshaft to the transfer case. Push forks allow your vehicle to travel over uneven terrain without breaking anything. This is important whether you hit a pothole or veer off the road.
Symptoms of a Failed Push Fork
If you suspect your push forks are broken, you’ll probably notice one or two things, but you might not know what’s causing the problem you’re experiencing. Below are the four most likely symptoms of a broken push fork.
#1 – Loud Clattering Noise
The push forks on your vehicle hold the driveshaft in place. This excess play causes the driveshaft to jump around with every bump and curve in the road, creating a loud noise. You may hear this rattle noise if your vehicle bounces a little too much, especially on uneven terrain. A broken thrust yoke can cause a rattle, but keep in mind that there are other possible causes for this noise.
#2 – Excessive Vibration
If the driveshaft is not secured tightly while driving, the whole system will be out of balance. The driveshaft rotates at high speeds while driving, so if it is not in a constant position, it will create vibrations throughout the vehicle.
#3 – Howling Noise
This is not the most common symptom of a failed thrust yoke, but a thrust yoke that lacks sufficient grease can cause a whining noise. Check the sliding forks and try adding a bit more grease if you hear squealing and suspect the sliding forks.
#4 – Rubbing or squeaking noises
This is usually caused by other driveshaft issues and not the slip forks, but if the slip forks are damaged, they can cause creaking or squeaking noises. It all depends on what is slipping into the worn sliding forks and causing these noises while driving.
Sliding Forks vs Fixed Forks?When looking at different driveshafts, you will notice two main types: sliding forks and fixed forks. The difference between the two is what moves when driving over uneven terrain.
With a sliding yoke, the yoke itself slides out of the transfer case when driving over uneven terrain. The driveshaft is a fixed length and this slippage allows the axle to move without completely destroying the driveshaft. With a fixed yoke, there is no movement in the transfer case and the driveshaft itself expands and contracts to meet the demands of the road.
There are no advantages or disadvantages to either system under normal driving conditions, but a fixed yoke has some advantages when driving off-road. This allows for sharper angles of motion and a larger range of motion.
How much free play should there be in a sliding fork?
The amount of free play in a slip fork really depends on the type of vehicle and the overall size of the slip fork and splined shaft. The important factor is that at least 2 inches of the splined shaft remain inside the sliding fork.
This means that with an 8 inch spline you can have up to 6 inches of free play, but with a 6 inch spline you don’t want more than 4 inches of free play. However, as you move down and start pushing the sliding yoke up and down, there should be no further movement on the splines.
Replacing or Repairing the Push Fork
The push fork is a vehicle component that requires regular maintenance, and if you don’t regularly use fresh grease, problems can occur.
But the good news is that as long as the lack of grease didn’t damage the splines, all you need to do is pump plenty of new grease into the slip yoke and it should clear up any problems that it has!
