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Home >> Ford Truck >> 1988 >> Bronco Full Size V8-351 5.8L >> Repair and Diagnosis >> Transmission and Drivetrain >> Drive/Propeller Shafts, Bearings and Joints >> Testing and Inspection >> Driveline Angles >> Driveline Angle Check

Driveline Angle Check

1. Raise the vehicle on a drive-on type hoist or back onto a front-end alignment rack. Jounce the vehicle to normalize the suspension. This ensures that the suspension components are in the normal-load condition.

NOTE: Driveline angles are given in relation to a 0° longitudinal (fore-aft) Unibody frame rail angle and are specified for individual components. Check the specifications for the engine, driveshaft and pinion angle.




2. Measure the Ride Height. The vehicle must be in the curb weight (unloaded) condition. Find the recorded ride height in the Driveline Angle chart. The specified driveline angles correspond to the measured ride height.

3. Driveline angles are measured with a Pinion Angle Level Gauge, T68P-4602-A or equivalent, as described in Step 4, or with an adjustable bubble (spirit level) protractor as described in Step 5. The protractor is used when the tool kit is not available or when the angles to be measured are more than 12°. All angles should be read within 1/2° with the tool or protractor held plumb on a clean, flat surface.




4. DRIVELINE ANGLE CHECK WITH A PINION ANGLE LEVEL GAUGE, T68P-4602-A (or equivalent). Place the vee magnet of the tool on the bottom of the vehicle frame as shown and calibrate the tool to a 0° bubble reading. This gives the 0° frame angle. Take and average the readings from both sides to obtain a more accurate reading. Driveline Angle Correction




Check the engine angle by rotating the driveshaft until one transmission slip yoke ear is parallel to the floor. Remove the retaining snap ring from the yoke. Install the Pinion Angle Level Gauge and record the angle reading. If the angle reading differs from the specified angle by 1° or more, proceed to Engine Angle Adjustment and neutralize the engine and transmission mounts. With the Engine Angle at specifications, check the Driveshaft and Pinion Angles. Re-install the snap ring.

To check the driveshaft angle, rotate the driveshaft so one driveshaft yoke ear is parallel to the floor. Remove the retaining snap ring from the yoke. Install the magnetic Pinion Angle Level Gauge on the U-Joint bearing cup and record the angle reading. Reinstall the snap ring. Check the Pinion Angle and if both or either reading is not to specifications, refer to Driveshaft and Pinion Angle Adjustment. Driveline Angle Correction




To check the Pinion angle, rotate the driveshaft so that one ear of the rear axle yoke is parallel to the floor. Remove the retaining snap ring from the yoke. Install the Pinion Angle Level Gauge and record the reading. If the reading is not to specifications, refer to Driveshaft and Pinion Angle Adjustment. Driveline Angle Correction




5. DRIVELINE ANGLE CHECK WITH ADJUSTABLE BUBBLE (SPIRIT LEVEL) PROTRACTOR: Place the protractor on the bottom of the vehicle frame directly below the front driver/passenger seat. This gives the 0° frame angle. Take and average the readings from both sides to obtain a more accurate reading. Calibrate the level to a 0° bubble reading.




NOTE: When using a bubble (spirit level) protractor, the angles are read from the 0° frame angle. The 90° mark on the protractor is read as the 0° frame angle. For example, when the protractor is placed on the component and the protractor reads 85°, the component angle is actually 5°.




To check the Engine Angle, rotate the driveshaft until one transmission slip yoke ear is parallel to the floor. Place the protractor so it is flush against the slip yoke ear. Make sure the protractor is not resting against any portion of the driveshaft assembly. Record the angle reading. If the engine angle reading differs from the specified angle by 1° or more, proceed to Engine Angle adjustment and normalize the engine and transmission mounts. Refer to diagnosis and testing. With the Engine Angle at specifications, check the driveshaft and pinion angles. Refer to angle specifications.




To check the Driveshaft Angle, place the protractor on any portion of the driveshaft tube so the plane surface of the protractor is flush against the bottom surface of the tube and parallel to the floor.

Record the reading. Check the Pinion Angle and if both or either reading is not to specifications, refer to Driveshaft and Pinion Angle Adjustment. Driveline Angle Correction




To check the Pinion Angle, place the protractor in a vertical position so it is flush against two rear axle cover retaining bolts. Rotate the protractor bubble indicator so the 90° marks align with the indexing marks. Calibrate the bubble to the "level" marking and read the protractor. For example, if the protractor indicates a reading of 85°, the Pinion Angle reading is 5°. Record the reading. If the reading is not to specifications, refer to Driveshaft and Pinion Angle Adjustment. Driveline Angle Correction




6. Road test to verify resolution of condition. If driveline angle correction and driveline runout/ balance procedures (refer to Driveshaft Balancing-Strobe and Transducer Method) do not eliminate the vibration condition, the axle ring gear and pinion gear set should be checked for backlash variation. Remove the axle cover plate as described in the appropriate Rear Axle. Measure ring gear backlash on thirty consecutive ring gear teeth and note the variation between the high and low readings. If over 0.10mm (0.004 inch) replace the gear set as described in the appropriate Rear Axle.
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