8 Most Common GMC Sierra Problems | Buyer Warning!

The GMC Sierra is a truck that many Americans rely on each year for working and going on adventures.

But what are the most common GMC Sierra problems? A buyer warning.

Although the GMC Sierra typically rates average or above average when it comes to reliability when compared to other full-size trucks on the market, the Sierra is not free from having issues. With regular inspections and keeping up with the maintenance schedule, you should be able to avoid major repairs and get many good years from your GMC Sierra, however, there are some more minor issues that have come up due to the design and construction of the truck.

Common GMC Sierra Problems 1 1 8 Most Common GMC Sierra Problems | Buyer Warning!

Table of Contents

What common issues do GMC Sierras have?

The most common GMC Sierra problems include the following issues: low-quality headlights, weak  door handles, strange noises from the upper steering shaft, bad mode door actuator, fuel pump issues, a failing four-wheel-drive transfer case sensor/selector, and an inaccurate fuel level sensor.

Although these types of issues may seem concerning, and rightfully so if you are planning on spending good money purchasing a GMC Sierra, these are not problems that will lead to your becoming inoperable.

By sticking to the GMC Sierra routine maintenance schedule and having your vehicle inspected regularly by a GMC Technician or your local mechanic, you should easily be able to reach 200,000 miles or more.

When it comes to these common problems that some GMC Sierra owners encounter throughout the life of their vehicle, typically the repairs are quite simple and do not cost a lot of money.

Let us take a look at these common problems, find out what causes them, how to fix them if they do occur, and how much you could expect to pay for these types of repairs. 

To gather all the information we need to see what common solutions are available to address these common problems and how much they could cost you, we have consulted other GMC Sierra owners, GMC technicians, and both local and national auto repair shops. All of these sources have extensive knowledge and experience addressing these common problems and they have made information easily available for you and other GMC Sierra owners. 

Are GMC Sierras dependable?

Overall, yes, GMC Sierras are dependable vehicles that should last a minimum of 200,000 miles without the need for any major repairs if the truck is properly maintained and the maintenance schedule is followed. 

Additionally, the GMC Sierra has a top-tier safety rating, and a reputation for high performance and towing capabilities. Also, its resale value does not depreciate as much as other vehicles. It is for these reasons, even considering that GMC Sierras can be more expensive than other trucks, the GMC Sierra is the 5th most popular truck sold in the United States.

What are the most common GMC Sierra problems?

Even the most reliable and dependable vehicles are sure to have some problems that occur due to how the vehicle was designed or manufactured. Many times these common problems require more minor repairs that cost less and that typically do not become apparent until after the vehicle leaves the dealership. Here is a breakdown of some of those common problems that GMC Sierra owners may encounter.

Common GMC Sierra Problems 1 8 Most Common GMC Sierra Problems | Buyer Warning!

Four-wheel-drive transfer case position sensors/selector fail

The transfer case contains settings in a 4WD vehicle that makes it possible to drive on harsh road conditions or to off-road with your truck. However, when you need to make a transfer shift in 4WD but the case position selector switch does not work, it can create some problems.

With the GMC Sierra, sometimes the transfer case position selector and senors can fail for no apparent reason. Other times, it could be because of one of these three reasons. 

  1. Dirt and water: Dirt and water that enter the four-wheel-drive transfer case can damage the wiring and engine encoder. Also, any corrosion that accumulates on the harness can create problems as well. If your transfer case or harness acquires significant damage, the computer could begin to make inaccurate resistance readings and make unnecessary shifts. To prevent this from happening, you should consider applying an undercoating to the undercarriage of your GMC Sierra and always get a full car wash after any off-road adventure. 
  2. Tire size and pressure: Having uneven tire sizes can cause some problems with the transfer case position sensors due to malfunctioning differentials. Also, even a slightly deflated tire could create resistance when shifting between 2WD and 4WD. To help prevent these types of issues, you should always make sure you have the proper tire size on your truck and that all the tires are the same size. Additionally, make sure you are checking your tire pressure regularly and keeping them properly inflated at all times. 
  3. Shaft seal failure: A bad shaft seal can cause hydraulic fluid to leak from the four-wheel-drive transfer case. A hydraulic fluid leak can cause issues when shifting between 2WD and 4Wd as well as cause the senors or selector to eventually fail. 

If you need to replace the entire four-wheel-drive transfer case motor, selector, and sensors in your GMC Sierra you may be looking at a minimum repair cost of about $500 or more. If you need to replace the hydraulic fluid in the transfer case, repairs could be around $112. If you have a failed shaft seal, you may be looking at an additional cost somewhere between $366 and $433 to replace the seal. 

Fuel level sensor

If your fuel level sensor goes bad on your GMC Sierra, you may begin to notice that your fuel gauge is showing incorrect fuel levels. Maybe you fill up your tank but it still shows that you only have ¾ of a tank. Or maybe the inaccurate fuel level sensor has caused you to run out of gas because it was showing you a ¼ of a tank when in reality you were running on fumes. 

The good news is that if the issue is only the fuel level sensor, you can easily get a replacement for as low as $60, and as high as $200 with a seal. The bad news is that an inaccurate fuel level gauge could be a sign that you have a larger issue. It could indicate that your fuel pump is going out and that you may need to have it replaced. If you need to replace the fuel pump, it can cost between $687 and $926. 

Erratic speedometer and gauges

Many GMC Sierra owners have reported that their instrument panel containing all the different gauges, including the speedometer, started to act erratically and unpredictably. This made it hard to keep track of vehicle speed, RPMs, fuel levels, and other vital information.

The good news is that if you encounter this issue with your GMC Sierra, GMC is aware of this problem and they have agreed to cover it under warranty for up to 7-years or 70,000 miles. The bad news is that you still might have to pay between $88 and $111 to have the problem diagnosed.

Once diagnosed, the instrument cluster needs to be sent out to a repair facility. 

Poor quality headlights

Some models and years of the GMC Sierra are known to have headlights that are of low quality and that do not properly illuminate the road when driving at night. 

GMC owners also indicated that there was no visible difference in brightness between the low-beam and high-beam settings. Driving at night without enough light is not only annoying but is also dangerous. This is especially true for people who often drive outside of the city on rural state highways and country roads. 

You can expect to pay anywhere from a couple of hundred dollars to $2,000 to have all new headlight assemblies installed in your GMC Sierra. A cheaper alternative may be to have fog lights installed on your truck to be used at night in addition to the stock headlights.

Weak interior door handles

Some years and models of the GMC Sierra have reported broken interior door handles after only moderate use. The use of cheap low-quality plastic for the interior door handles is to blame for this. The good news is that you can find high-quality replacement handles for under $20 and you most likely will be able to do the installation yourself, even if you are not very mechanically inclined. 

Strange noises from the upper steering shaft

Some GMC Sierra owners reported that the upper immediate shaft can create some rattling and clunking sounds. Additionally, some owners reported that their steering wheel seemed like it was going to pop when driving at lower speeds.

The quickest and cheapest way to address this problem is to grease the steering shaft periodically. When the sound returns after some time, simply apply another layer of grease to the steering shaft. 

Faulty mode door actuator (A/C – Heater)

Another issue that some GMC Sierras have encountered through the years pertains to the vehicle’s heating and cooling (HVAC) system. Specifically, the source of the problem tended to be the mode door actuator. 

A faulty mode door actuator can cause the heater to only blow out cold while the AC then comes out hot. Or, sometimes the AC didn’t work at all, or if it did work, it did not work the way it was supposed to. 

The only fix for this problem is to have the HVAC blend door actuator placed. To replace the mode door actuator, a GMC Sierra owner is looking at a repair cost anywhere between $290 and $331.

Fuel pump issues

Some earlier models of the GMC Sierra, like the 1999 GMC Sierra 1500, have been known to have problems with the fuel pump. Some people reported that their truck stalled out frequently and failed to restart. Others reported that they had trouble turning the engine over or that the truck would run for a few miles and then die with no warning.

In the 1999 GMC Sierra 1500, sometimes it would only take 10,000 miles for these issues to develop in the fuel pump. For other models, it took much longer, however, the same problems occurred. 

The only way to address these types of fuel pump issues is to do a full fuel pump replacement. A full fuel pump replacement can cost anywhere between $687 and $926.

What kind of regular maintenance does a GMC Sierra require?

As mentioned before, aside from these common problems that some GMC Sierra owners have reported over the years, the GMC Sierra is still a dependable vehicle favored by many truck owners.

No matter which truck you purchase, there is a good chance that you are going to have some minor issues to take care of throughout the time you own the vehicle. However, if the vehicle is properly maintained and any issues are taken care of immediately, you should be able to get 200,000, 250,000, or even 300,000 miles from your GMC Sierra. Let us take a brief look at what a regular maintenance schedule may look like for the GMC Sierra.

Every 7,500 miles

Every 7,500 miles, or every 6-months, you will want to bring your GMC Sierra in for a regular check-up. During this check-up, you should have a tire rotation, safety inspection, and oil and oil filter change. 

Additionally, your mechanic or GMC Technician should take a quick look at your Sierra’s brakes, belts, and hoses, as well as look for any fluid leaks that could be a cause of concern. They may also check all your fluid levels including coolant levels, transmission fluid, and windshield wiper fluid.  

Every 22,500 miles

Every 22,500 miles, in addition to everything that you typically have done at the 7,500-mile mark, you are going to want to have the cabin air filter replaced and transfer case fluid changed. 

Every 45,000 miles

Every 45,000 miles, you will want to have your evaporative control system inspected. Also, you will have to have your mechanic inspect and/or replace the engine air filter and Sierra’s transmission, transfer case, brake, and clutch fluid.

Your mechanic may also inspect your spark plugs and spark plug wires at this time and look for wear and tear on your Sierra and whether or not they should be replaced. 

At 150,000 miles

Once you hit 150,000 miles, then it is time to have some additional procedures done to your GMC Sierra to help it reach that 200,000+ milestone. At 150,000, a GMC Sierra should have its engine cooling system drained and then refilled and the accessory drive belts should be inspected for any signs of damage like fraying or cracking. 

How much does regular maintenance cost for a GMC Sierra?

On average, it will cost an owner of a GMC Sierra around $8,948 to properly maintain their vehicle through the first 10-years. Annual maintenance costs start at around $319 in the first year and then can hit closer to $1,659 in the 10th year.

Here is a quick breakdown of estimated annual maintenance costs for the GMC Sierra through the first 10 years.

  • 1st year: $319
  • 2nd year: $370
  • 3rd year: $452
  • 4th year: $582
  • 5th year: $690
  • 6th year: $860
  • 7th year: $1,205
  • 8th year: $1,342
  • 9th year: $1,469
  • 10th year: $1,659