Pinpoint Test S: Vehicle Pulsates Or Shudders In a Straight Line (Straight Line Driveline Wind-up)

Four Wheel Drive (4WD) Systems - 2-Speed Torque-On-Demand

Pinpoint Test S: Vehicle Pulsates or Shudders in a Straight Line (Straightline Driveline Wind-up)

Normal Operation

In order for the 4WD (Four-Wheel Drive) 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 S : VEHICLE PULSATES OR SHUDDERS IN A STRAIGHT LINE (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.

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?

Yes
GO to S2.
No
RETURN the vehicle to the customer. ADVISE about correct 4WD (Four-Wheel Drive) system operation and normal vehicle behavior.

S2 CHECK FOR MATCHING WHEEL AND TIRE SIZES

- Check the wheel and tire sizes.

Do the 4 wheels and tire sizes match?

Yes
GO to S3.
No
ADVISE the customer that 4WD (Four-Wheel Drive) systems require 4 matched, correctly inflated, correctly maintained tires to operate correctly.

S3 CHECK TIRE WEAR

- Check each of the 4 tires for wear.

Are the 4 tires worn evenly?

Yes
GO to S4.
No
ADVISE the customer that 4WD (Four-Wheel Drive) systems require 4 matched, correctly inflated, correctly rotated tires to operate correctly.

S4 CHECK TIRE INFLATION PRESSURE

- Check the inflation pressure in each tire. Refer to the Safety Certification Label on driver door or door pillar.

Are the tire inflation pressures correct?

Yes
GO to S5.
No
ADJUST the tire pressure as necessary. TEST the vehicle for normal operation. ADVISE the customer that 4WD (Four-Wheel Drive) systems require 4 matched, correctly inflated, correctly maintained tires to operate correctly.

S5 CHECK THE FRONT AND REAR AXLE RATIOS

- Check that front and rear axle ratios match.

Do the front and rear axle ratios match?

Yes
RETURN the vehicle to the customer and ADVISE about correct 4WD (Four-Wheel Drive) system usage and normal vehicle behavior.
No
CHECK the VC (Vehicle Certification) label. INSTALL the correct axle(s). TEST the system for normal operation.