Special Application Services

• Allison Transmission™ Vehicles Only: Replace external transmission filter at first engine oil change only.
• Vehicles with Dual Wheels: Check dual wheel nut torque at 160 km/100 mi, 1 600 km/ 1,000 mi and 9 700 km/6,000 mi.
• Severe Commercial Use Vehicles Only: Lubricate chassis components every 5 000 km/ 3,000 mi.
• Have underbody flushing service performed once a year.

    See also:

    Customer Assistance for Text Telephone (TTY) Users (U.S. and Canada)
    To assist customers who are deaf, hard of hearing, or speech impaired and who use Text Telephones (TTYs), GMC has TTY equipment available at its Customer Assistance Center. Any TTY user can communicat ...

    Fast Idle System
    If the vehicle has this feature it is available only with cruise control. The manual fast idle switch is operated using the cruise control buttons located on the left hand side of the steering wheel. ...

    Park Tilt Mirrors
    If the vehicle has the memory package, the passenger and/or driver mirror tilts to a preselected position when the vehicle is in R (Reverse). This feature lets the driver view the curb when parallel p ...