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Smoothing out drive-away Ford truck shudder

Some 2008-2009 Ford F-250 and F-350 Super Duty trucks with single rear wheels (SRW) and F-350 trucks with dual rear wheels (DRW) 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 the vehicle is overloaded.

Trailer tongue weight should be limited to 10% to 20% of the total trailer weight, depending on the type of hitch. If towing a fifth wheel or gooseneck trailer, the centerline of the hitch should be 2 inches forward of the rear axle centerline.

Refer to the Owners Guide and Certification label on the driver’s door for maximum payload and cargo capacity.

The technician should discuss with the customer how the vehicle is driven the majority of the time (loaded or unloaded), as adjusting the driveline angle per this may result in a slight shudder with the vehicle unloaded.

Due to changes in the suspension of the 2008-2009 F Super Duty, the repair procedure is different from previous model years (1999-2007 F Super Duty). The driveshaft should feature an optimum 3-degree operating angle. If necessary, change the pinion angle to the axle and the height of the center bearing (CB) carrier bracket.

1. Check the angle of the engine and record this value. The best location to accomplish this is on the starter, since this is the most parallel to the engine crankshaft. The special tool Anglemaster II Driveline Inclinometer/Protractor #164-R2402 or equivalent should be used.

2. Check the angle of the coupling shaft and record its value.

3. Check the angle of the driveshaft and record its value.

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.

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.

CALCULATE 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) – Coupling shaft 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 – driveshaft angle = Operating Angle “B.”

3. Operating Angle “C”: Using the recorded angles for the driveshaft and pinion, subtract the smaller number from the larger number to obtain Operating Angle “C.”

Driveshaft angle – pinion angle = Operating Angle “C.”

NOTE: The combined totals should have an optimum 3-degree operating angle.

CHANGE OPERATING ANGLE ON F-SUPER DUTY 250/350 4X2 SRW 156-INCH AND 172-INCH WHEELBASE

Install a 1-degree or 2-degree pinion angle shim (wide end at front) to pitch the axle. This is typically all that is needed to correct or minimize the concern.

CHANGE OPERATING ANGLE ON F-SUPER DUTY 250/350 4X4 SRW 156-INCH AND 172-INCH WHEELBASE

1. Install a 1-degree or 2-degree pinion angle shim (wide end at front) to pitch the axle, or replace the spacer block with a 2-inch 0-degree block.

2. Replace the frame support bracket to raise CB height, if required.

3. Measure operating angle for a second time. Continue to Step 4 only if additional adjustments are necessary to obtain an optimum 3-degree operating angle.

4. A shim kit may be required to lower CB height to lessen unloaded truck shudder. Up to three shims per side may be placed under the support bracket. When refastening the carrier bracket, use the bolt listed or a 7/16-14 grade 5 bolt may be substituted, providing that it extends at least three threads past the nut. Torque the bolt to a value of 52 lb-ft (70 Nm).

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