The shock absorbers of your Chevrolet Avalanche help to isolate the bed and body from the road as you drive. Without shocks or with worn-out shocks, your truck would ride as if it were a dingy in constantly choppy water. If you’ve seen cars driving down the road bouncing like a person on a bungee cord, you’ve seen prime examples of motorists that need new shocks. In extreme cases, the affected wheel/corner can actually be seen to jump off the surface of the road. Shock absorbers that aren’t doing their job are dangerous because they degrade the amount of control you have of your vehicle, well as causing irregular tire wear issues, causing a tread wear pattern known as cupping. This is because the perceived weight on the affected corner increases and decreases. This article will cover front and rear shock absorber replacement on Chevrolet Avalanche models up through the 2006 model year.
Three Ways to Check Your Avalanche’s Shock Absorbers
There are three ways you can tell if you need to install new shocks on your Chevy Avalanche.
- If the shocks are wet and oily where the piston enters the shock body, they’re leaking and need to be replaced.
- Run your palm across your tires. If you feel hills and valleys, that’s cupping and indicates shocks that need replacement.
- The last test is called the ‘jounce test.’ Place your knee on the bumper at one corner or the truck and firmly and quickly push down on the bumper and release it. Now count the number of times the body bounces. You want to see no more than three bounces, but preferably only two. Three times indicates shocks that are borderline. Anything more than three times and they really need to be replaced.
Tools and Equipment You’ll Need for This Repair Procedure
You’re going to need a socket set for this job. If your truck sits too low to the ground to get under it comfortably and safely, you’ll also need at least one jack stand and a jack. Also wear safety glasses.
Getting Ready to Do the Repair
Park the truck on a flat and level surface. This means your driveway, if there is any sort of an angle to your driveway, don’t use it. Set the parking brake firmly and place blocks in front of and behind one rear wheel if doing the fronts or both. If you’re doing the rears, block both sides of one front wheel. This keeps the truck from rolling forward or backwards while you’re working.
Replacing the Front Shocks on Your Avalanche
Some repair manuals say you have to remove the front wheel to get the shock out. If you can reach the nut on the top of the shock at the top of the coil tower without removing the wheel, you won’t need to remove the tire. Otherwise, you’ll need to remove the tires after lifting the front end.
- After lifting the front of the truck, place jack stands under the frame rail behind the wheels and carefully lower the truck onto the stands. If so equipped, disconnect the Electronic Suspension Control (ESC) connector by grasping the tabs and rotating counterclockwise until the connector is unlocked. (numbers 1 & 2 in the above image) **
- Place the jack cup under the ball joint, leaving room under the shock and raise the jack until it reaches the control arm. Now raise it a few more pumps to take the load because the shock absorber on some years of Avalanche is also the lower motion limit stop for suspension travel.
- Using the ratchet and a socket of the proper size (usually 9/16 inch) turn the nut counterclockwise and remove it. Refer to the picture to get an idea of what this area looks like.
- Next, from under the center of the lower control arm, remove the two bolts securing the bottom of the shock absorber to the control arm. These bolts are usually either 9/16 or 5/8 inch. Again, refer to the supplied image to see what you’re looking at.
- Installation is completed in the reverse order of removal. Torque the upper and lower nuts and bolts to 59 foot-pounds (Model Year 2005).
** After disconnecting the wiring harness, hold the connector body on the shock (the tenon) with a wrench and remove the nut and upper insulator. During reinstallation, torque the nut to 15 foot-pounds.
Note on Avalanche Front Shocks
On most vehicles, the front suspension has mechanical means to limit suspension travel that aren’t limited to the front shocks. However, on the Avalanche, the front shocks are the travel limiters for the suspension. Due to this fact, “They look like they fit” won’t cut it. Replacement shocks have to the same exact size and of the same exact strength or they most likely will fail early. Your 20 minute shock replacement job just turned into a suspension overhaul that will take hours.
Rear Shock Absorber Replacement
Replacing the rear shocks is even easier than the fronts.
- Lift the rear of the truck by the differential housing.
- Place jack stands under the frame in front of both rear wheels and slowly lower the truck onto the stands. Leave the jack engaged so you can use it to help ease the installation.
- Remove the upper and lower shock absorber nuts and bolts and remove the old shocks.
- Align the shock so the upper mounts line up. Slide the bolt through and thread the nut in place. Leave it slightly loose so you can manipulate the shock still.
- Position the shock in the lower mount and slide the bolt in. Thread the nut onto the bolt.
- Torque the upper and lower nuts/bolts to 70 foot-pounds (2005 model-year Avalanche).
ESC-Equipped Vehicles– Disconnect the ESC connector and air line from the shocks before removing the shocks. (Image above)
Note: The directions above are generalizations. Each year and sub-model (15/25) will have minor differences, although the layout will not change much from year to year. For example, rear shocks on 15 Series trucks are outboard of the frame rail while they are inboard on 25 Series trucks.
Always wear safety glasses when working under your vehicle. You’ve only got one set of eyes and even a small metal or rust chip can permanently damage them.
Never attempt this type of repair with your Avalanche parked on an incline such as most driveways. Even with good jack stands, the tugging and pushing you need to do during this repair could cause the truck to fall.
Extra Notes and Helpful Hints
Some models and years of the Chevy Avalanche came equipped with an electronic ride control. You will need to refer to your owner’s manual to see if your truck is one of these. If so, follow the directions in the owner’s manual to deactivate it. You will also need special shock absorbers. If not, two of the most popular brands of shocks for trucks that are used mostly on the road are Monroe (for “Stock” ride quality) and Bilstein (for a more performance type ride) The Monroe part numbers are 39104 for the front and 911506 for the rear for non-ESC-equipped vehicles. It is highly recommended that you pick up a motor manual for your vehicle to get the proper torque specs for your truck. Improper torqueing of the nuts and bolts securing the shock absorbers or ESC connectors can result in damage to the shocks or mounts, the ESC connector, or, if an inadequate amount of torque is applied, the nuts can loosen and fall out.
While these directions cover most possibilities, each year and trim/submodel will vary at least slightly. For this reason it is highly recommended that you pick up a motor/repair manual so you at least have the torque specifications for everything handy.