Rick's Free Auto Repair Advice

Shuddering on acceleration Ford AWD, 4WD

Fix a shuddering on acceleration on Ford

Ford has issued a service bulletin #08-21-11 to address a shuddering on acceleration Ford AWD, 4WD and applies to the vehicles listed below.


1997-08 Ford Expedition, Explorer

2006-08 F-150

2007-08 Explorer Sport Trac

2008 F-150


Ford describes the problem as either a shuddering on acceleration, a binding in slow speed turns, or noise from the front driveline or transfer case. All of these concerns occur when in the AWD/Auto 4×4 mode. Ford finds that the problem may be caused by different circumference tires. Here’s their recommended testing procedure.


1) Check the tires and tire pressure to make sure they’re all the same size and tire pressures are within specs.


2) Disconnect all wiring to the transfer case.


3) Road test the vehicle. If the shuddering is still there, this bulletin does NOT apply. If the shuddering is gone, measure the tires as described in Step 4


4) Using a flexible tailor’s tape, (not a metal tape measure), wrap the tape around each tire and record the circumference.


Add the dimensions of the 2 front tires and divide by 2

Add the dimensions of the 2 rear tries and divide by 2


The difference between the front and rear results must be less than 1/2”. If the result is greater than ½”, replace the smallest circumference tire and then re-measure

©, 2015 Rick Muscoplat

Posted on by Rick Muscoplat

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