If you’re staring at a $90,000 window sticker for a brand-new Denali and feeling a physical pain in your chest, you aren't alone. It’s ridiculous. Honestly, the truck market has gone a bit sideways lately, which is exactly why the 2016 GMC Sierra 2500 is suddenly the "it" truck for people who actually know how to turn a wrench or haul a trailer. It sits in that perfect sweet spot. It’s old enough to have depreciated into a sane price bracket, yet new enough to have the creature comforts that won't make your spouse complain on a long road trip.
Most people don’t realize that 2016 was a pivot point for GMC.
They didn't just slap a new grill on it and call it a day. They introduced things like Digital Steering Assist on the higher trims, which makes a three-quarter-ton truck feel less like a school bus and more like a massive SUV. It’s subtle. You notice it most when you’re trying to back a 30-foot fifth-wheel into a tight campsite at dusk. Your forearms aren’t screaming at you by the time you’re unhooked.
The Duramax LML vs. Everything Else
Let’s talk about the elephant in the engine bay. The 2016 GMC Sierra 2500 comes with the LML version of the 6.6L Duramax turbodiesel. Now, some internet "experts" will tell you to hold out for the 2017 L5P engine because it has more horsepower. Sure. Fine. But the LML is a workhorse that has been poked, prodded, and perfected by the aftermarket for years.
It pumps out 397 horsepower and 765 lb-ft of torque.
Is it the 1,000+ lb-ft you see in the 2026 models? No. But do you actually need that to pull a horse trailer or a skid steer? Probably not. The Allison 1000 six-speed automatic transmission paired with this engine is legendary for a reason. It shifts with a sort of deliberate, heavy mechanical precision that gives you confidence when you're descending a 6% grade with a full load.
There is a catch, though. The CP4 high-pressure fuel pump. If you’re looking at buying a 2016, you need to check if the previous owner installed a lift pump or a CP3 conversion. The CP4 is known—infamously—to fail if it gets even a hint of contaminated fuel, and when it goes, it takes the whole fuel system with it. It’s a $10,000 nightmare. A lot of guys run fuel additives every single fill-up just to keep that pump lubricated. It’s a small price for peace of mind.
Inside the Cabin: When GMC Beat Silverado
GMC has always tried to position the Sierra as the "professional grade" sibling to the Chevy Silverado. In 2016, that gap felt wider than usual. The interior of a 2500 Denali from this year is still a very nice place to be. We're talking real aluminum trim, not that painted plastic junk you see in some competitors.
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The 2016 model year was also when Apple CarPlay and Android Auto finally arrived.
This is huge. It’s the difference between a truck that feels "old tech" and one that feels modern. Being able to plug in your iPhone and have Waze or Spotify pop up on the 8-inch IntelliLink screen changes the whole ownership experience. You aren't stuck with GM's clunky native navigation system.
The seats are wide. They’re built for people who eat steak. If you find one with the ventilated seat option, jump on it. GMC’s cooling seats actually blow cold air, unlike some luxury brands that just circulate ambient cabin air. However, keep an eye on the leather on the driver's side bolster. Even on the lower-mileage trucks, that's where they always start to crack first because people "slide" out of the cab instead of using the running boards.
Handling the Weight
Heavy duty trucks aren't supposed to ride like Cadillacs. If you buy a 2016 GMC Sierra 2500 and expect a cloud-like experience, you’re going to be disappointed. It’s stiff. Empty, it will bounce you around over expansion joints on the highway.
But throw 2,500 pounds in the bed? It settles down instantly.
The suspension geometry on the 2016 models was refined to handle the increased GVWR (Gross Vehicle Weight Rating) that came with the 2015 redesign. It feels planted. You don't get that "tail wagging the dog" feeling when a semi-truck passes you at 75 mph.
Common Gremlins to Watch For
No truck is perfect, and the 2016 Sierra has its quirks.
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- DEF Tank Sensors: The Diesel Exhaust Fluid sensors are notoriously finicky. You’ll get a "Speed Limited to 55 MPH" warning because a $50 sensor thinks the fluid is poor quality.
- Steering Clunk: Some owners report a rhythmic clunking in the steering column. Often, it’s just the intermediate shaft needing some grease or replacement, but it drives people crazy.
- HID Headlights: 2016 saw the introduction of new HID projector headlamps with LED signatures. They look amazing, but if a ballast goes out, it’s not a cheap fix like a $15 halogen bulb.
The Gas Alternative: Is the 6.0L Worth It?
Not everyone needs the diesel. If you’re only towing occasionally or you have a short commute, the 6.0L Vortec V8 is a tank. It’s an older design—iron block, pushrod—and it’s thirsty. You’ll get 10-12 mpg regardless of whether you're going uphill, downhill, or being towed by a crane.
But it’s cheap to maintain.
You don't have to worry about DEF, DPF soot filters, or expensive fuel pumps. For a business owner who needs a reliable 2500-series truck that won't rack up massive repair bills, the 6.0L is a hidden gem. It just works.
Real-World Towing Capacity
The 2016 GMC Sierra 2500 with the Duramax is rated to tow up to 14,500 pounds with a conventional hitch. If you go with a fifth-wheel or gooseneck setup, that number jumps to 18,000 pounds.
Think about that for a second.
That is more than enough for almost any recreational trailer on the market. Most campers you see at the local RV park weigh between 7,000 and 11,000 pounds. This truck won't even feel them. The integrated trailer brake controller is positioned perfectly to the left of the steering wheel, making it easy to reach in an emergency.
The "Professional Grade" Aesthetic
The 2016 facelift was, in my opinion, the peak of GMC truck design. It was before they went to the massive, oversized C-shaped LED lights and the multi-pro tailgates that have too many moving parts. It’s a handsome, squared-off truck. The wheel arches are slightly flared, giving it a muscular stance without looking like it's trying too hard.
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If you find a 2500 in "Stone Blue Metallic" or "Iridium Metallic," you’ve hit the jackpot. Those colors hold their depth incredibly well if they've been waxed even once or twice.
What to Check Before You Buy
When you go to look at a 2016 GMC Sierra 2500, bring a flashlight. Get under the truck. Check the rocker panels and the bed corners for rust, especially if the truck spent its life in the salt belt. GMC improved their corrosion resistance, but they aren't invincible.
Check the service records for transmission fluid changes. The Allison is tough, but it likes clean fluid. If the fluid on the dipstick smells burnt or looks like chocolate milk, walk away. There are plenty of other trucks out there.
Also, look at the tires. Replacing a set of load-range E tires on a 2500 isn't cheap. You’re looking at $1,200 to $1,600 for a decent set of Michelin Defenders or BFGoodrich KO2s. If the tires are bald, use that as a bargaining chip to knock $1,500 off the price.
Final Actionable Steps
If you’re serious about picking up one of these trucks, start by narrowing down your "must-haves." Do you actually need the Denali trim, or would an SLT with the Preferred Package give you the same leather and Bose audio for $5,000 less?
- Verify the Fuel System: Ask specifically if the CP4 pump has been addressed or if a lift pump (like a FASS or AirDog) has been installed to protect it.
- Test the Digital Steering Assist: Drive an SLE and then drive a Denali back-to-back. See if you can feel the difference in steering weight at low speeds.
- Check the RPO Codes: Look at the sticker inside the glove box. Look for "Z71" if you want the off-road suspension or "K40" for the exhaust brake, which is essential for heavy towing.
- Scan for "Soft" Codes: Use an OBDII scanner to see if there are any pending codes for the DEF system, even if the Check Engine light isn't on yet.
The 2016 GMC Sierra 2500 is a rare beast. It’s a modern luxury vehicle masquerading as a blue-collar workhorse. It doesn't have the "over-teched" feel of the 2024+ models, but it certainly doesn't feel like a relic of the past. If you find one with under 150,000 miles that hasn't been abused, buy it. You likely won't see a truck built this solidly again.