How to balance a driveshaft
Things You'll Need
2 screw-type hose clamps
Put the car on a lift and support the rear axle so the rear wheels can freely rotate. Place the car in neutral and release the parking brake.
Take off the rear wheels, then install lug nuts so the flat sides are against the brake drums.
Get an assistant to sit in the driver's seat. Lift the vehicle, making sure to set the lift's lock.
Ask your assistant to start the engine and to drive in high gear to a speed of approximately 40 to 50 mph. Do not run for long periods or faster than 55 mph since this can cause damage to the engine or transmission because there is no load.
Raise your chalk near the drive shaft's rear, using a stand for support.
Raise it until you make contact with the rotating shaft. The mark shows the location of the shaft's heavy spot.
Ask your assistant to step on the brakes gently, then turn the engine off.
Install two hose clamps side by side onto the drive shaft, aligning the screw assembly 180 degrees opposite the chalk mark.
Tighten the clamps. Ask your assistant to turn the engine on again and accelerate to 40 to 50 mph. If you detect no vibration, replace the wheels, lower the vehicle and take it on the road for a test. If you detect vibration, equally rotate the two clamps away from each other the same amount. Tighten the clamps and continue tightening until you detect no vibration. When you feel no vibration, replace the wheels, and lower the vehicle for a road test.Source: ehow.com