Driveline Angle

Driveline angularity is the angular relationship between the engine crankshaft, the driveshaft, and the rear axle pinion. Factors determining driveline angularity include ride height, rear spring, and engine mounts.

Fig 1: Identifying Driveline Angle

Courtesy of FORD MOTOR CO.

Calculate the driveline operating angles as follows.

1. Preliminary setup procedures.
   1. Inspect the U-joints for correct operation.
   2. Park the vehicle on a level surface such as a drive-on hoist, or back onto a front end alignment rack.
   3. Verify the curb position ride height is within specifications with the vehicle unloaded, and all of the tires inflated to their normal operating pressures.
   4. Rotate the transmission output yoke until vertical. This will simplify taking measurements.
   5. Calibrate the special tool by placing tool on clean, flat level section of the frame rail and press the ALT-ZERO button.
2. Using the special tool, measure the slope of the components. Record the measurements and the direction of the component's slope.
   Fig 2: Measuring Slope Of Components

   Courtesy of FORD MOTOR CO.
   Fig 3: Example For Calculating U-Joint Operating Angles

   Courtesy of FORD MOTOR CO.
3. Calculate the difference in the slope of the components to determine the U-joint operating angle.
   • When two connected components slope in the same direction, subtract the smaller number from the largest to find the U-joint operating angle. When two connected components slope in the opposite direction, add the measurements to find the U-joint operating angle.
   • The U-joint operating angle is the angle formed by two yokes connected by a cross and bearing kit. Ideally, the operating angles on each end of the driveshaft must:
     • be equal or within one degree of each other.
     • have a three degree maximum operating angle.
     • have at least one-half of one degree continuous operating angle.

If the tires and driveline angle are not the cause, carry out the NVH tests to determine whether the concern is caused by a condition in the axle. For additional information, refer to NOISE, VIBRATION AND HARSHNESS .