Offroad Trailblazers and Envoys

Inner & Outer Tie Rod Replacement

Tie rods connect the rack and pinion to the steering knuckles.  They essentially transfer the lateral motion of the steering ram to the tires.  They go through a lot of abuse, especially off road.  Every bump, steering input, and braking motion put stress on the components. Tie rods are generally made up of two components.  […]

Rear Wheel Bearing Replacement

I recently had a vibration problem in my 03 LS that didn’t go away after I replaced u-joints, balanced the tires, and checked the front wheel uni-bearing hubs (which were previously replaced). I also noticed a squeak and at times a rumble that seemed to be coming from the general direction of the rear axle […]

Rear Axle G80 Differential Rebuild

My G80 quit some time ago. I don’t know about you, but I like both of my rear wheels to lock up when I need them, so a rebuild was in order. Most other platforms simply ditch their G80’s in favor of something stronger. Unfortunately, us 8.0″ rear end Trailvoy’s don’t have that option. In […]

Front Wheel Hub / Bearing Replacement

This article covers how to diagnose and replace a front wheel bearing on a TrailBlazer (or Envoy). Wheel bearings are a complex and fairly expensive item for a TrailBlazer.  They serve to support the vertical weight of the vehicle, transfer lateral turning forces from the wheel to the body, transfer the power from the front […]

Front Axle 4WD Disconnect Rebuild

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 […]

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 […]

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 […]