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Home >> Ford >> 2012 >> Mustang Base, 2D Coupe, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 557 (Four Wheel Drive (4WD) Systems) >> Diagnosis And Testing >> Four Wheel Drive (4WD) Systems - Electronic Shift >> Pinpoint Tests >> Pinpoint Test H: Vehicle Pulsates or Shudders in a Straight Line (Straightline Driveline Wind-up) >> Pinpoint Test H: Vehicle Pulsates Or Shudders In A Straight Line (STRAIGHTLINE Driveline Wind-Up)

Pinpoint Test H: Vehicle Pulsates Or Shudders In A Straight Line (STRAIGHTLINE Driveline Wind-Up)

WARNING: This page is about a different car, the 2014 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
WARNING: When directed to drive the vehicle as part of this test, drive the vehicle on a hard surface in an area without traffic to prevent a crash. Failure to follow these instructions may result in personal injury.
NOTE: 4X4 high/low (4H/4L) is not intended for driving on hard/dry surfaces.
  1. H1 VERIFY THE CONCERN 
    • Drive the vehicle and shift from 2H to 4H. There should be minimal wind-up in 4H mode during straight line maneuvers (wind-up in turns is normal; 4X4 high/low is not intended for driving on hard/dry surfaces).

    Is excessive wind-up present? 

    • Yes  : GO to H2  .
    • No  : RETURN the vehicle to the customer. ADVISE about correct system operation and normal vehicle behavior.
  2. H2 CHECK FOR MATCHING WHEEL AND TIRE SIZES 
    • Check the wheel and tire sizes.

    Do the 4 wheel and tire sizes match? 

    • Yes  : GO to H3  .
    • No  : ADVISE the customer that 4WD  systems require 4 matched, correctly inflated, correctly maintained tires to operate correctly.
  3. H3 CHECK TIRE WEAR 
    • Check each of the 4 tires for wear.

    Are the 4 tires worn evenly? 

    • Yes  : GO to H4  .
    • No  : ADVISE the customer that Four-Wheel Drive (4WD) systems require 4 matched, correctly inflated, correctly maintained tires to operate correctly.
  4. H4 CHECK TIRE INFLATION PRESSURE 
    • Check the inflation pressure in each tire. Refer to VC label.

    Are the tire inflation pressures correct? 

    • Yes  : GO to H5  .
    • No  : ADJUST the tire pressure as necessary. TEST the vehicle for normal operation. ADVISE the customer that 4WD  systems require 4 matched, correctly inflated, correctly maintained tires to operate correctly.
  5. H5 CHECK THE FRONT AND REAR AXLE RATIOS 

    Do the front and rear axle ratios match? 

    • Yes  : RETURN the vehicle to the customer and ADVISE about correct 4WD  usage and normal vehicle behavior.
    • No  : CHECK the vehicle VC label. INSTALL the correct axle(s). REFER to DRIVELINE SYSTEM - GENERAL INFORMATION .
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