The 1996-2006 generation of GM full-size pickups is among the most popular and trusted trucks on the road. Sold as the Chevrolet Silverado and GMC Sierra, these trucks are available in a number of cab and box configurations, with different lengths, engine and transmission options depending on the model.
If you are looking to purchase a used GM pickup – especially one with high mileage – there are a few points you should consider and several areas to look at to make sure you’re getting a quality truck that will last for many more miles.
Avoid Known Issues with Chevy/GMC Trucks
While the GM trucks are generally regarded as durable and reliable, there are a few problem areas you’ll want to watch out for. This goes for any truck you’re buying since they often spend their lives hauling, towing and pushing heavy loads, which tends to wear many mechanical components out. Consider these common Chevy and GMC truck issues before buying:
1. Hub and Bearing Issues
Even the best hubs and bearings will wear out. In the case of the GM pickups, the front wheel hubs often start to show play. You will detect this as a vibration or shudder in the front end of the truck that gets worse over time.
An easy diagnosis is to lift the front end of the truck up and see if the wheels move from side to side when you knock firmly or apply pressure to the inside of the wheel — any side-to-side movement of the wheels means the hubs and bearings likely need to be replaced. It is unsafe to drive for long with worn hubs and bearings, as failure at high speed can make it very difficult to control the truck and could result in a fatal accident.
2. Tie Rod Ends
Your front tie rod ends come in two sets of pairs: an inner and outer rod at each front wheel. These rods connect your wheels to the steering rack. Any play in the tie rod ends will affect the accuracy and responsiveness of your steering and can also put your wheels out of alignment.
It is important to replace a truck’s tie rod ends when you start seeing signs of play. Failure at speed can mean a loss of steering control and could cause an accident. This is fairly easy to check with the front end of the truck up. When you pull on the tie rod ends, there shouldn’t be any movement between the rod and the boot.
3. Axle Seals
An axle seal fluid leak can be a big hassle if it gets bad enough. These small seals are designed to keep the fluid in the differential housing. Over time, these rubber seals get hard and brittle and can crack, allowing fluid to escape. A small leak won’t cause differential problems, but any leak will eventually get worse.
Take the time to inspect the axle seals of any used truck you plan to buy and make note of any leaks at the axle stubs or differential because the seals will need to be replaced if they are leaking. Replacement of the seals themselves is not complicated, but it typically first involves dropping the differential, which is can be a lot of work.
4. Water Pumps and Thermostat Housings
There are many potential locations for coolant to leak from an engine, but with the GMC and Chevy pickups, the water pump and thermostat/thermostat assembly housing are common sources of leaks. The thin gaskets wear out over time and let coolant seep out. If a gasket cracks all the way through, the coolant leak can quickly become severe, disabling your truck. If an engine overheats, damage can quickly be done to key components.
Wipe around the water pump and thermostat areas with a rag and run the truck for a few minutes to see if you can locate any coolant leaks before buying. Depending on the engine you have, you may not have easy access to check for leaks, so use a flashlight to check for wet spots.
RWD and 4×4 vehicles all use a driveshaft to deliver power from the transmission to the rear axle. A pair of U-joints at the front of the driveshaft and another at the rear account for the difference in height and alignment of the shaft as the suspension travels up and down.
The original equipment U-joints in the Silverado and Sierra pickups are prone to wear around the 120,000-mile mark – or sooner depending on usage – and should be checked. If you’re considering buying a used high mileage truck, try to get it up on a hoist and check for play in the U-joints. Another sign that a truck’s u joints may need to be replaced is if you hear a clunk when shifting from drive to reverse or a squeaking noise when you start to move.
An experienced mechanic can replace these joints quickly, but a beginner may find it challenging on their own.
While brake pads are normal wear parts that need to be replaced on any vehicle, the 1999-2006 Chevy Silverado and GMC Sierra are known to have problems with their aluminum brake calipers. These lightweight calipers are used front and rear and were made from aluminum to save weight. They tend to bind and hang up causing the pads to wear unevenly — especially at the rear.
Pull off the wheels and check the brake pads if possible before buying a used pickup to see if you’ll need to change the calipers or not. A lack of braking power for any reason can lead to reduced stopping power, so always pay close attention to brakes when buying a used truck.
If you aren’t able to take the wheels off before buying a truck, check when you get it home. It is often it is a good idea to plan on doing a brake job on any used vehicle that you purchase and you can use this as an opportunity to check conditions of the calipers as well.
Being Prepared Can Help You Make the Best Selection
This used Silverado and Sierra pickup buying guide arms you with tips to avoid some of the most common GM pickup issues. Watch for these points and overall condition of the 1999-2006 series full-size GM trucks so that you can be prepared for any potential issues that your new truck may have before buying it.
All trucks will need some repairs and maintenance as they get up there in miles, but knowing what to look for can help you be prepared for any additional expenses that may come with your new truck so that you can make an informed buying decision.