With new trucks selling in the neighborhood of $40,000-60,000 or higher, budget-conscious buyers are looking more often to the used market or holding on to their older trucks and freshening them up with more modern appointments and features. Well-maintained late-model trucks can easily go up to 300,000 miles or more with proper care and maintenance. When we found this clean ’04 Avalanche 1500 Z71 on Craigslist for just $6,100, we couldn’t pass that deal up. With 163,000 miles on the clock, it was in need of a few fixes, but nothing so major that we didn’t think we could tackle them with a few new parts and some help from friends.
The seller knocked off $200 for a non-functioning speedometer, and for $5,900, we had a good starting point for a comfortable, capable, budget-friendly work-and-play vehicle. All-in with all of the parts and upgrades to this point, we’re still well below $10,000. Most of the repairs and upgrades are possible with basic tools and knowledge. Labor can be one of the biggest costs involved, so the more you can do yourself or with friends, the more money you’ll save.
Interior and Exterior Lighting
Inside and out, the lighting of the Avalanche needed some upgrading. The original headlight lenses were a little crusty and oxidized after more than a decade of driving. We initially tried one of the ubiquitous headlamp lens polishing kits but knew that was only a temporary fix that we’d have to re-do every few months to keep them looking fresh. Instead, we decided we’d take advantage of the new technology and style that has emerged over the last decade and give the Avy a fresh, contemporary look. To that end, we installed “Eagle Eye” LED accent headlights, driving lights, and LED brake lights from Anzo USA.
Although the lights looked good on the company’s website, the results in person were nothing short of stunning. The new lights made a major difference to the Avalanche’s looks, turning a few heads and making it look a lot newer and more modern. The original third brake light was still technically functioning but was so sun-baked that it looked as black as the plastic cladding surrounding it. We got a new replacement LED third brake light from RockAuto.com to round out the exterior light upgrades. Finally, we replaced the reverse light bulbs with a pair of LED units from Anzo USA, completing the premium, high-tech look.
On the inside, the Avalanche’s speedometer was non-functional at purchase, and some of the backlighting of the HVAC and steering wheel controls was also burned out. After some web searching, we found a mobile gauge cluster repair business specializing in GMT800 trucks. We had all the gauge motors replaced, as well as upgrading gauge and HVAC control backlighting to LEDs. While we were at it, we had a transmission gauge added—although we needed a specialist to activate it, which required sending the cluster off to Michigan. Finally, the leather wrapping and rocker buttons on the steering wheel had seen better days. We had a local upholstery shop rewrap the wheel for a thick, grippy feel, and the mobile gauge specialist also replaced the worn rocker buttons and added LED backlighting.
Shocks and Brakes
With the interior and lighting taken care of, we focused on getting the Avalanche’s running gear up to optimal order. We replaced the tired original shock absorbers with some Rancho RS5000X shocks front and rear, providing a smooth ride. We were also shocked to discover that the Avalanche still had its original brake rotors. The brake pads were also getting pretty thin and were in need of replacement. The rear parking brake shoes were also literally falling apart in our hands, so we added those to the replacement list. We got new Powerstop pads, rotors, parking-brake shoes, and shocks from RockAuto.com, and we employed the help of an experienced mechanic friend to help out with the replacement. Also, we discovered a leaky CV boot on one of the front half-shafts. Now was the perfect time to take care of it.
Oil, Sensors, and Plugs
Finally, the workhorse LM7 5.3L iron-block V-8 wasn’t running at its full potential. At part throttle, the engine ran smoothly and without drama. But when we put the hammer down, we were greeted with copious detonation and could tell the engine computer was pulling a lot of spark out, delivering far less than its advertised 295 hp and 330 lb-ft of torque. No more than a week later, we started getting the dreaded check engine light. After running an OBD-II scan, we discovered a faulty knock sensor. Once we pulled the manifold off and actually had a look at it ourselves, it was easy to see why. The rear sensor was severely corroded. We replaced both knock sensors, the wiring harness, and the intake manifold gaskets, then replaced the spark plugs and wires, all from RockAuto.com. Like the brake rotors, we were flabbergasted to find out that it appeared our spark plugs were original too! While we were at it, we changed the oil with Amsoil 5W-30 full synthetic and used one of Amsoil’s replacement oil filters. With the knock sensors, plugs and oil changed, the Gen-III small-block was finally performing up to its potential, with snappy throttle response, and the kind of power we expected.
While we have more and bigger things planned in the Avalanche’s future, it’s finally to a point where we could happily drive it as-is for years to come. These fixes and refreshes will provide a great starting point for future upgrades.
**NOTE: Prices may vary. Check with different outlets for best price. We found RockAuto.com had competitive prices, and an easy-to-use, comprehensive parts search tool.**
Negotiated Purchase, 2004 Chevrolet Avalanche 1500 Z71 – $5,900
Spark Plugs – Denso 5077 – $3.50 x 8 = $28.00
Spark Plug Wires – AC Delco 748HH – $59.68
Knock Sensors – AC Delco 213-3521 – $48.78 x 2 – $97.56
Knock Sensor Harness – $59.95
Fel-Pro MS98016T Intake Manifold Gasket Set – $55.78
Cardone Select 66-1009 Front Half-Shaft – $66.78
Dorman LED Third Brake Light – $59.95
6 Quarts Amsoil 5W-30 Synthetic – $11.70 per quart x 6 – $70.20
Amsoil Oil Filter – $14.15
Rancho RS5000X shocks – Set of four – $199.96
Power Stop Autospecialty Brake Rotors and Pads (Front and Rear) – $217.95
AC Delco Rear Parking Brake Kit – $64.35
Anzo USA LED 111312 Headlights – $351.53
Anzo USA LED 511067 Turn Signal/Running Lights – $159.04
Anzo LED Tail Lights – $237.14
Anzo 3157 LED Reverse Light Bulbs – $14.01 x 2 – $28.02
Gauge Cluster Rebuild & HVAC Backlighting (Parts & Labor) – $360.00
Trans Temp Gauge Activation – $65.00
Steering Wheel Re-wrap – $250.00
Total Parts – $2,445.04
Total Parts & Vehicle – $8,345.04