Propshaft Balancing

There are three different methods of balancing a propshaft. Select from the following:

Before you begin

Be sure to check for water inside the propshaft, especially if the vehicle has a trailer hitch. Vehicles that tow boats are more susceptible to having water in the propshaft.
Make sure the propshaft does not have undercoating applied to it, if it does remove the undercoating and road test the vehicle again.
If propshaft runout has been eliminated as a cause of the first order propshaft speed related vibration then there must be a component that is out-of-balance. This component is spinning the same speed as the propshaft; it might even be the propshaft.
One example of such a component is a parking brake drum that some heavier trucks use. This drum is attached to the output shaft of the transmission. Many times the park brake drum must be indexed correctly to stay in balance with the rest of the propshaft system. Double check this park brake drum for correct alignment.
The best way to correct a first order propshaft speed related vibration is to system balance the propshaft. Consult the vehicle manufacturer's service manual for system balance procedures.

Strobe balancing the propshaft assembly with the EVA.

The Trial and Error Method

Place hose clamps 180 degrees from the high spot of propshaft runout for a starting point.
Add, remove, rotate, or spread the hose clamps to come up with an acceptable system balance.

The Alternative Method

Remove the propshaft and send it to a reputable driveline repair shop to be balanced. The disadvantage of this method is that only the propshaft gets balanced. The pinion flange and transmission output shafts are unaffected.

This page was last modified Thursday, March 05, 2009 09:02:31 PM