Auto Repairing 2008-2009 Ford F-250, F-350 Single Rear Wheel (Srw)—Shudder Or Vibration On Acceleration (Especially When Loaded)
ISSUE Some 2008-2009 F-Super Duty 250/350 vehicles with Single Rear Wheels (SRW) may exhibit an excessive drive-away shudder or vibration under moderate to heavy acceleration from a stop, especially when heavily loaded. This may be due to driveline angle. The shudder or vibration may be more evident while towing a trailer or if vehicle is over loaded. • Trailer tongue weight should be 10-20 percent of the total trailer weight, depending on the hitch. • If towing a 5th wheel trailer or gooseneck trailer the centerline of the hitch should be two (2) inches in front of the rear axle centerline. • Refer to the Owners Guide and Certification Label on the drivers door for maximum payload and cargo capacity.
ACTION Follow the Service Procedure steps to correct the condition. 1. Check the angle of the engine and record its value. The best location to accomplish this is on the starter since it is the most parallel to the engines crankshaft. The special tool Anglemaster II Driveline Inclinometer / Protractor 164-R2402 or equivalent should be used. (Figure 1) 2. Check the angle of the coupling shaft and record its value. (Figure 1) 3. Check the angle of the driveshaft and record its value. (Figure 1) 4. Rotate the driveshaft until the flange U-joint cup is facing downward. In this position the flange is the closest point parallel to the pinion gear. (Figure 2) 5. Using the U-joint bearing cup attached to the pinion flange as the reference point for the pinion gear, check the angle of the pinion flange and record its value. (Figure 2) Calculate Operating Angles: Use the worksheet below tocalculate the three operating angles. 1. Operating Angle (A) Using the recorded angles for the engine and the coupling shaft, subtract the smaller number from the larger number to obtain operating angle (A). Engine angle (degrees) ____ – Couplingshaft angle (degrees) ____ = Operating Angle (A) ____ 2. Operating Angle (B) Using the recorded angles for the coupling shaft and driveshaft, subtract the smaller number from the larger number to obtain operating angle (B). Coupling shaft angle (degrees) ____ – Driveshaft angle (degrees) ____ = Operating Angle (B)____ 3. Operating Angle (C) Using the recorded angles for the driveshaft and pinion, subtract the smaller number form the larger number to obtain operating angle (C). Driveshaft angle (degrees) ____ – Pinion angle(degrees) ____ = Operating Angle (C)____
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