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Home >> Ford >> 2008 >> Expedition EL RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 1 (Four Wheel Drive (4WD) Systems) >> Diagnostic Tests >> Four Wheel Drive (4WD) Systems - 2-Speed Torque-On-Demand >> Pinpoint Tests >> Pinpoint Test S: Straight-line Driveline Wind-up >> Pinpoint Test S: Straight-Line Driveline Wind-Up

Pinpoint Test S: Straight-Line Driveline Wind-Up

WARNING: This page is about a different variant/trim than selected.
NOTE: 4X4 is not intended for driving on hard/dry surfaces; using 4X4 mode while driving on these surfaces may produce noises like intermittent clunking, but will not damage driveline components.
  1. S1 VERIFY THE CONCERN 
    • Drive the vehicle and shift from 2H mode to 4H mode. There should be minimal wind-up in 4H mode during straightline maneuvers (wind-up in turns is normal; 4H/4L is not intended for driving on hard/dry surfaces).
    • Is excessive wind-up present? 
    1. YES  : Go to  S2.
    2. NO  : RETURN the vehicle to the customer. ADVISE about correct 4WD system operation and normal vehicle behavior.
  2. S2 CHECK FOR MATCHING WHEEL AND TIRE SIZES 
    • Check the wheel and tire sizes.
    • Do the 4 wheel and tire sizes match? 
    1. YES  : Go to  S3.
    2. NO  : ADVISE the customer that 4WD systems require 4 matched, correctly inflated, correctly maintained tires to operate correctly.
  3. S3 CHECK TIRE WEAR 
    • Check each of the 4 tires for wear.
    • Are the 4 tires worn evenly? 
    1. YES  : Go to  S4.
    2. NO  : ADVISE the customer that 4WD systems require 4 matched, correctly inflated, correctly rotated tires to operate correctly.
  4. S4 CHECK TIRE INFLATION PRESSURE 
    • Check the inflation pressure in each tire. Refer to Vehicle Certification (VC) label.
    • Are the tire inflation pressures correct? 
    1. YES  : Go to  S5.
    2. 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. S5 CHECK THE FRONT AND REAR AXLE RATIOS 
    1. YES  : RETURN the vehicle to the customer and ADVISE about correct 4WD system usage and normal vehicle behavior.
    2. NO  : CHECK the Vehicle Identification Label (VIL). INSTALL the correct axle(s). REFER to DRIVELINE SYSTEM - GENERAL INFORMATION article. TEST the system for normal operation.
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