These are some questions that our driveline experts are commonly asked. Click one of the questions below to see it’s answer.
The slip yoke should have ¾” before it would fully bottom out on the transmission output. Trucks and offroad vehicles with the outboard slip yoke may require more if they have extra suspension travel.
The driveshaft may have worn parts causing an imbalance. The driveshaft may have lost a balance weight. The tube may have been twisted causing runout of the driveshaft. To help in the diagnosis, distinguish if the vibration is felt in the seat and floor, or in the steering wheel. A driveshaft vibration is typically felt in the seat or floor.
The slip yoke bound on the output spline when stopping and as you unloaded it, it is suddenly allowed to move to the length change required by differential and suspension movement. A coating of grease can be applied to the inside of the slip yoke. The slip yoke can be replaced with one that has a nickel coating which resists this binding. You may have the universal joint wear or slip and spline wear which you are feeling as a thump or clunk when taking off and stopping. This condition should be repaired immediately.
The lift kit has created universal joint angle problems which will need to be corrected. On a two piece driveshaft, the higher u-joint angles, although they may be equal, are resisting the natural “swivel” action required to rotate smoothly. This is typically more prevalent in the newer pickups with higher torque. The driveshaft instead is thrown around within the steady bearing bracket transmitting a “shudder” to the driver.
When removing the bearing from the midship stub, it is possible to change the position of the stub enough to cause a vibration. The driveshaft may have been reinstalled in the vehicle out of phase, or 180 degrees from where the assembly was balanced.
Worn universal joints causing excessive movement before engaging all the drivetrain components. Other drivetrain components are worn to cause excessive movement. This includes the transmission, transfer case and differential.
Yes! In most automotive cases, there are conversion universal joints that will allow you to match two different u-joint sizes. The strength of the driveshaft will remain no stronger than the smallest side of the conversion universal joint.
The driveshaft yokes may have been damaged when the u-joints were removed or installed. The tube may have been dented or creased when removing or installing the u-joints causing the driveshaft to no longer run true. The parts of the driveshaft may have been assembled out of phase. If the universal joint was an original part held in by nylon injection, the driveshaft will need to be rebalanced now that the new u-joint is centered with snap rings.
The difference is in the theory of operation. A single universal joint operating at an angle, will transmit inconsistent velocity at the output. Two universal joints that are in phase and the input and output shafts are on the same plane, create constant velocity. This means that the output velocity will be identical to the input velocity. The inconsistent velocity will occur after the first joint and be counteracted by the second. For the constant velocity joint to maintain equal angles at all times, a centering device of some kind is typically used.
Often it is found on a u-bolt style end yoke. If the u-bolt is over-tightened, it will distort the bearing cap, causing premature wear of the u-joint. This can be verified if the two bearings in the driveshaft yoke are okay. If damage to the yoke was not noticed during replacement of the first universal joint, the next u-joints will not last as long as they should.
In most cases a driveshaft can be altered to the new length. There are a couple of factors to consider. If the new length is beyond the safe operating speed of the tube size, a larger tube or two piece driveshaft will need to be used. If the original driveshaft uses swaged tube where the weld yokes are designed for smaller tube than the center, a new driveshaft may be more economical.
No, the two piece driveshafts in automotive applications are balanced as an assembly. To balance one piece only may actually have an adverse effect on the system balance once reinstalled.
Yes! Most automotive applications can be supplied an aluminum driveshaft. Aluminum driveshafts are often 1/3 lighter than steel. There are benefits beyond just weight that an aluminum driveshaft will give you.
Yes. We will need the measurements of your old driveshaft or the vehicle that you need the driveshaft for. When you contact us, we can assist you in the gathering the necessary information.
Most all driveshafts can be shortened. The weld yoke is removed from the tube, the tube shortened to the required length, the weld yoke pressed back into the tube and welded into place. The driveshaft must then be rebalanced.
Increase the tubing diameter and/or wall thickness. Increase the universal joint size or change it to a stronger version. Often the non-greaseable u-joints are not through drilled which will give it more strength.
Our high speed balancing equipment can often ensure a better running driveshaft. We would make the determination whether it is a driveshaft balance problem.
The driveshaft could be causing the vibration that you feel. It may be caused by worn components or universal joints. It may have sustained accident damage that has not been repaired. There are also many other causes of vibrations in vehicles and we can assist in diagnosing yours.
The driveshaft may have been reinstalled incorrectly or out of phase. The universal joint angles have changed. These will need to be corrected, or a custom driveshaft supplied to compensate for the new height.