re: Truck Rear Differential question

quote:

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TSB
10-06-06
"Special Advisory"

SOME 2009-2010 F-150 VEHICLES EQUIPPED WITH A 6R80 TRANSMISSION MAY EXHIBIT A SHUDDER WHICH IS FELT DURING LOW SPEED LIGHT THROTTLE ACCELERATION BETWEEN 30-35 MPH (48-56 KM/H), THE SHUDDER/VIBRATION EVENT OCCURS TYPICALLY WHEN THE VECHICLE DOWNSHIFTS AND THEN IS FOLLOWED BY A LIGHT THROTTLE TIP-IN. See TSB for complete details Effective date 4/01/2010


TSB
10-22-11

Some 2010 F-150 vehicles equipped with a 4.6L engine, 6R80 transmission and built between 6/1/2009 and 12/1/2009 may exhibit a shudder which is felt during low speed, light throttle acceleration between 25-45 MPH (40-72 Km/h). The shudder/vibration event typically occurs when the vehicle downshifts and is followed by a light throttle tip-in. A new calibration is available to address the concern.

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I'm leaning toward this but I would change rearend oil first. It's an easy job. Use synthetic oil and you won't need to put the additive in it.