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Most Common Repairs On GMT900 Silverado And Sierra Trucks: Dorman OE FIX

Hey, I’m Miriam from Dorman Products, and today we’re going to talk about some common problems you might find when you’re working on a second-generation Chevy Silverado or a third-gen GMC Sierra, better known as the GMT900 series.

Now, you should also take a look at this video if you own one of these trucks. If you’re a DIYer, it’ll lend you a little insight into some vehicle-specific areas to check out. And if you’re not, you can ask your mechanic to keep an eye on a few things, so hardworking trucks can keep working hard.

The Silverado and Sierra are reliable trucks, that’s part of why there are literally millions of them traveling America’s roads. However, the GMC900 models have a few issues specific to them, so it can pay to keep an eye on those items. Or have your mechanic take a moment to check them.

It also makes sense to examine a few of these areas, if you’re considering the purchase of a used truck. Many of these problems can be caught during a pre-purchase inspection, and quite a few can be fixed before they spiral into a situation that leaves you on the side of the road.

The most common problem you’re likely to find on a General Motors truck is on the lug nuts. Like so many other makes, GM uses a lug nut with a thin veneer cap. We’ve all gotten jammed up with these before. If the caps start loosening, you can’t easily remove the lug nut. And in the worst cases, the nut has to be extracted using tools that often damage the wheels.

If a set of lug nuts feels real snug in your flip socket, gets those things out of service. And check out the set of our OE fix one-piece lug nuts. And being that they’re so easy to install before they become a problem, and easy to install in general, this is a perfect spot to check for an ambitious DIYer who owns a truck of this generation.

Another common failure spot on these is something I check immediately. When a vehicle comes in for service, any mechanic worth his hourly rate rolls down the left front window to prevent being locked out of a car. The window drags on these trucks are a weak point. The cables can cut into the guides, and the large runs of cable can attract dirt and debris that shorten the life of the rig.

I see this a lot on work vehicles when drivers stop and pay tolls, get lunch from the drive-thru, or receive directions for trailer hookups. When I get in the truck and the window binds or rolls slowly, I add that to my estimate before it gets stuck open or closed on the driver.

While this is getting to be on the outside of what most DIYers want to do in the driveway, our unit is a perfect replacement for a weekend wrencher, because it includes the motor and the regulator together. If you’re not sure which piece is failing, and you don’t want to go into the door panel twice, or you don’t trust your diagnostic skills are as good as Miriam’s, having the whole assembly can save you from blowing multiple Saturday afternoons on this job.

Our unit also has addition cable guides and sheathing, so whether you’re doing this yourself or asking your shop to repair this regulator, if you request a dormant unit, you’re getting a part that’s built to avoid failing again anytime soon.

Miriam, I want to bring up another part that I’ve seen fail myself, and that’s the heater hose fitting. These things are plastic, and they get brittle. I’ve seen this on the 99 to 06 Silverado and Sierras. And that problem seems to have carried through to this generation.

GM uses quick-disconnect fittings at the heater core. Over time, the aged plastic becomes ripe for failure. When I hear a customer complaining of no heat or the smell of syrup, this is the spot I check instinctively. Our upgrade piece is stainless, so the concerns about future failure are effectively eliminated. I’d like to point out to my DIY crew out there that this is not a difficult piece to fit, and fixing the problem before your truck starts dropping coolant is a fine idea.

Access is a little cramped, and you’re definitely going to need a QD tool, so make sure to order one of those if you don’t own a set. And given the limited access, a better quality tool will pay for itself here. I’d also encourage anyone doing this to purchase OEM-style constant tension clamps. Resist the urge to use a more common worm gear clamp here. Since you’re hooking up to a used hose, the new fitting will start to take a set, and our constant tension pieces keep you from chasing the leak as the rubber relaxes.

And while you’re in there, you may want to check out the Y that comes off the surge tank. It’s another common leak point, and we make an aluminum Y to replace that. Our kit to nip that up also comes with those constant tension clamps that Maria mentioned.

Next up is a real beaty, the shift cable bushing kit. GM expects you to buy and replace an entire shift cable, when the silly bushing finally gets tired and wears out. Fortunately, we sell just the bushing. And as a tech, I love installing these. They’re so much more affordable, in parts and labor for my customers. The install is pretty easy on these. It can be a bit of a chore, but it’s definitely easier than replacing the whole cable.

The piece alone can disable a vehicle, so I would recommend buying one and just tucking it in the glove box. It’s made to fit a variety of GMs, but on these trucks you just need one bushing. So, you get an extra in the package. And, if you need any help on this one, Nick made a neat tips and tricks video on installing shift cable bushings, so check it out if you’re a DIYer, and you want to know what to do in the supermarket parking lot when that day finally comes for you.

I’m going to point out one other weak spot I see on these trucks, and that’s the cam phaser actuators, especially if I see dirty oil or that the oil is at the incorrect level, I start sniffing around. These trucks aren’t the old 350 of yester year. They are powerful and fuel-efficient trucks, but poor maintenance habits can cause a litany of issues. Often, I’ll find actuators causing strange noises. And, I’ve also come across some codes for variable valve timing systems, too.

But even on trucks with religious maintenance, these parts just wear out. Think of how many times these things actuate. So, what’s the fix for something like this? Obviously, a new actuator sounds a little beyond the scope of most DIYers. That’s correct, this is not a job for the faint of heart, however our Dorman OE fix cam phaser solenoids feature a strengthened copper core and additional oil flow passages. These extend the durability of the part, especially in severe conditions. It’s a great swap for a work truck that might be a little neglected.

And, there you have it folks. Whether you’re just checking out your own truck for potential issues that could crop up, or you’re a wrench looking for some sensitive areas to head off problems for your customers, these should help keep those Chevys rolling along. Thanks for watching our video on the top fixes for 2008 through 2014 Silverados and Sierras. For Dorman Products, this is Greaser. I’m Miriam, and we’ll see you next time.