Hoist Test

After a road test, but only after a road test, it is sometimes useful to do a similar test on a hoist. (Use an axle hoist not a frame hoist. An axle hoist will not change the driveline angles. If only a frame hoist is available, car stands should be used).
1. Elevate the front wheels slightly, check to make sure that both are turning, and run the engine up with the vehicle in gear.
2. Explore the speed range of interest using the drive/cruise/coast/float tests.
3. A coast down in NEUTRAL should also be conducted. If the vehicle is free of vibration when operating at a steady indicated speed and behaves very differently in drive and coast, an axle concern is likely.

Note, however, that a test on the hoist may produce different vibrations and noises than a road test because of the effect of the hoist on the front suspension. It is not unusual to find vibrations on the hoist that were not found in the road test and many times these may be ignored. If the condition that was found on the road can be duplicated on the hoist, a great deal of time can be saved by doing experiments on the hoist.