Driveline Angle
Driveline AngleDriveline Operating Angle:
Driveline operating angularity is the angular relationship between the input and output sides of any flex coupling or universal Joint. Some of the factors determining driveline angularity include ride height, rear spring, and engine mounts.
NOTE: See Steps 1 through 16 for front and rear flex coupling angles between joints 1, 2 and 3. Joint number 1 is the operating angle of the front flex coupler, number 2 is the operating angle of the center U-joint and number 3 is the operating angle of the rear flex coupler.
An incorrect driveline (pinion) angle can often be detected by examining the driving condition in which the vibration occurs.
^ A vibration during coastdown, from 72 to 56 km/h (45 to 35 mph) is often caused by an excessive angle at the axle (pinion nose downward).
^ A vibration during acceleration, from 56 to 72 km/h (35 to 45 mph) may indicate an excessive angle at the axle (pinion nose upward).
When these conditions exist, check the driveline operating angles.
1. CAUTION: Prior to checking driveline angularity, inspect the flex couplers and the U-joint for correct operation.
Check the vehicle for:
^ overload or sagging.
^ specified air pressures in all 4 tires.
^ loose axle mounts.
^ loose rear subframe-to-body mounts.
2. Normalize the suspension.
3. Drive the vehicle onto a drive-on hoist or front end alignment rack.
4. Inspect the suspension and chassis.
5. Remove the exhaust heat shield fasteners and slide the exhaust heat shield as far forward as possible to expose the driveshaft to axle flange coupling.
6. NOTE: The special too] contacts the flex coupling bolt sleeve to obtain an accurate reading.
NOTE: The bolt is serrated in the flange. The bolt should not be removed, only the nut.
Prepare to measure the front flex coupling operating angle (A).
1 Remove one of the nuts that attach the flex coupling to the transmission flange.
2 Install the special tool onto the bolt on the rear of the flex coupling and tighten the nut.
7. Place the special tool in the bracket slot with the special tool facing the passenger side and set the gauge to zero using the thumbscrew.
^ Remove the special tool and tighten the fastener to specification.
8. NOTE: The special tool must contact the flex coupling bolt sleeve to obtain an accurate reading.
NOTE: The bolt is serrated in the flange. The bolt should not be removed, only the nut.
Prepare to measure the front flex coupling operating angle (B).
1 Remove one of the nuts that attach the flex coupling to the front driveshaft.
2 Install the special tool onto the bolt on the front of the flex coupling and tighten the nut.
9. Place the special tool in the bracket slot with the special tool facing the passenger side and record the reading.
^ Remove the special tool and tighten the fastener to specification.
10. NOTE: The special tool must contact the flex coupling bolt sleeve to obtain an accurate reading.
NOTE: The bolt is serrated in the flange. The bolt should not be removed, only the nut.
Prepare to measure the rear flex coupling operating angle (c).
1 Remove one of the nuts that attach the flex coupling to the rear driveshaft.
2 Install the special tool onto the bolt on the rear of the flex coupling and tighten the nut.
11. Place the special tool in the bracket slot with the special tool facing the passenger side and record the reading.
^ Remove the special tools and tighten the fastener to specification.
12. NOTE: The special tool must contact the flex coupling bolt sleeve to obtain an accurate reading.
NOTE: The bolt is serrated in the flange. The bolt should not be removed, only the nut.
Prepare to measure the rear flex coupling operating angle (D).
1 Remove one of the nuts that attach the flex coupling to the pinion flange.
2 Install the special tool onto the bolt on the rear of the flex coupling and tighten the nut.
13. Place the special tool in the bracket slot with the special tool facing the passenger side and record the reading (D).
^ Remove the special tool and tighten the fastener to specification.
14. Calculate the operating angles of Joints 1, 2 and 3 as follows:
^ A-B = Joint 1
^ B-C = Joint 2
^ C-D =Joint 3
15. NOTE: To adjust the center support bearing adjusting washers, the exhaust heat shield must be removed.
NOTE: Left and right washers should be the same thickness.
NOTE: Two washers should not be assembled together.
Adjust the joint operating angles by varying the center support bearing adjusting washers.
16. Install the exhaust heat shield.
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.