Trailblazers and Envoys Offroad

Tech Docs

Torque Specs and other articles that may be helpful during your next project or repair.   Please contribute by submitting or discussing in our forum.

Various Vehicle Specs

4.2L 5.3L Years Details .: Torque Specs :. Lug Nuts X X 02-09 105 lbs/ft Brake Caliper Front Bolts X X 02-09 CV Axle Nut X X 02-09 103 lbs/ft Wheel Hub and Bearing Mounting Bolts X X 02-09 77 lbs/ft Outer Tie Rod X X 02-09 33 lbs/ft Inner Tie Rod X X 02-09 […]

Diagnosing the 4WD System

We run into many questions where the owner realizes the front tires are not engaging when in a 4WD mode. The first and easiest step is to check for the appropriate sounds from your system.  With the engine off, but the key in the accessory position, switch the 4WD switch from 2HI to 4HI.  You […]

Engine and Transmission Diagnostic Sheets

Below are trouble code diagnostic sheets for the TrailBlazer, Envoy, Rainier, Bravada, Ascender, and Saab 9-7 based on specific engines and model years. Year Engine Transmission LL8 4.2L I6 LM4 / LH6 5.3L V8 LS2 6.0L V8 (SS) LL8 4.2L I6 LM4 / LH6 5.3L V8 LS2 6.0L V8 (SS) 2002 PDF – – PDF […]

Transmission Technical Documents – 4L60e

Transmission Technical Documents – 4L60e

Through my research I’ve run across a few very helpful documents regarding the trailblazer transmission (the 4L60e).  I’ve amassed them here. Electronic Controls Document: Details of the internal wiring, pin-outs, and other electronic details. Hydraulic Schematic: (Left is the key document, right is the actual schematic file) Details of the internal hydraulic routing and their […]

Front Axle 4WD Disconnect

Front Axle 4WD Disconnect

Theory of operation, common failures, and rebuilding: Unit 56, above, is known as the front axle 4WD disconnect.  It resides on the passenger side of the oil pan, opposite of the front differential. The disconnect allows the front left and right wheels to spin independently of each other, and allows the front prop-shaft to remain […]

Transfer Case Operation: NVG 226 (NP8)

The New Venture Gear model NVG 226 transfer case is the dual speed, automatic, active transfer case in the Chevrolet TrailBlazer and GMC Envoy.  It provides five modes of operation: 2 HI Auto 4WD 4 HI 4 LO Neutral. General Operation: The Auto 4WD position allows the capability of an active transfer case, which provides […]

Wiring Diagrams

What size wire should I use?  Check this wire calculator: What lights should I use?  There is a great article hosted here that covers this question: A full write-up can be found here in our forums:

Auxiliary Light Aiming

DRIVING LIGHT AIMING Typically, driving lights are mounted above the front bumper about 14-30 inches from the ground to provide extra high beam illumination. Driving lights can be mounted below the bumper, although they will not be as effective because the light will hit the ground sooner and reduce the range of the light. Visual […]