GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC C-Series Medium Duty Truck B7 🢒 Engine 🢒 Engine Controls - 7.4L 🢒 Air Cleaner Outlet Rear Duct Replacement

Removal Procedure

    Object Number: 422645 Size: SH

    Important: Take care when handling the MAF. Do Not dent, puncture, or otherwise damage the honeywell located at the air inlet end of the MAF. Do Not touch the sensing elements or allow anything (including solvents and lubricants) to come in contact with them. A small amount of GM lubricant (P/N 99855406) may be used on the air duct only to aid in installation. Do Not drop or roughly handle the MAF.

  1. Remove the clamps (3) from the air cleaner outlet rear duct (2) to the throttle body.
  2. Remove the clamps (3) from the air cleaner outlet rear duct to the MAF sensor (4).
  3. Remove the air cleaner outlet rear duct from the vehicle.

Installation Procedure

    Object Number: 422645 Size: SH
  1. Install the air cleaner outlet rear duct to the vehicle.
  2. Install and tighten the clamps (3) to the air cleaner outlet rear duct to the MAF sensor (4).

    3. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  3. Install and tighten the clamps (3) to the air cleaner outlet rear duct to the throttle body.

    4. Tighten
    Tighten all clamp screws to 2.5 N·m (22 lb in).