Pinpoint Test AH: Straightline Driveline Wind-up

Four Wheel Drive (4WD) Systems - 1-Speed Torque-On-Demand

Pinpoint Tests

Pinpoint Test AH: Straightline Driveline Wind-up

Normal Operation

In order for the Four-Wheel Drive (4WD) system to function correctly, tires and wheels must be the same size, be in good condition and the front and rear axle ratios must match.

This pinpoint test is intended to diagnose the following:
- Unmatched tire sizes
- Unequal amounts of tire wear
- Unequal tire inflation pressures
- Unmatched front and rear axle ratios

PINPOINT TEST AH: STRAIGHTLINE DRIVELINE WIND-UP

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.

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AH1 VERIFY THE CONCERN

- Drive the vehicle and switch from 4X4 AUTO mode to 4X4 mode. There should be minimal wind-up in 4X4 mode during straight line maneuvers (wind-up in turns is normal; 4X4 mode is not intended for driving on hard/dry surfaces).
- Is excessive wind-up present?

Yes
GO to AH2.

No
RETURN the vehicle to the customer. ADVISE about correct 4WD system operation and normal vehicle behavior.

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AH2 CHECK FOR MATCHING WHEEL AND TIRE SIZES

- Check the wheel and tire sizes.
- Do the 4 wheel and tire sizes match?

Yes
GO to AH3.

No
ADVISE the customer that 4WD systems require 4 matched, correctly inflated, correctly maintained tires to operate correctly.

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AH3 CHECK TIRE WEAR

- Check each of the 4 tires for wear.
- Are the 4 tires worn evenly?

Yes
GO to AH4.

No
ADVISE the customer that 4WD systems require 4 matched, correctly inflated, correctly rotated tires to operate correctly.

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AH4 CHECK TIRE INFLATION PRESSURE

- Check the inflation pressure in each tire. Refer to Vehicle Certification (VC) label.
- Are the tire inflation pressures correct?

Yes
GO to AH5.

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.

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AH5 CHECK THE FRONT AND REAR AXLE RATIOS

- Check that front and rear axle ratios match. Refer to Driveline System - General Information Description and Operation.
- 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 Identification Label (VIL). INSTALL the correct axle(s). TEST the system for normal operation.

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