Some 2007-08 Ford Fusion, Mercury Milan and Lincoln MKZ models with all-wheel drive systems may produce a vibration in the drivetrain while being driven at highway speeds.
Ford says that the vibration often is accompanied by a howling noise, and that both problems are due either to an improperly indexed or out-of-balance rear driveshaft.
Start the repair by disconnecting the rear driveshaft and reindexing it to the rear diff flange as outlined in a repair manual.
Now go on a road test to see if the vibration and noise are gone. If they are, you're done with the fix.
If the symptoms remain, replace the rear prop shaft with an upgraded unit, part No. 8E5Z-4R602-A.
"Factory Fixes" is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. Mr. DePalma advises that techs always check with a dealer or repair information system for the latest revisions before starting to work on a vehicle. He can be reached via e-mail at [email protected].