Diesel Brothers is a new Discovery series that follows the crew from DieselSellerz as they build the baddest diesel trucks on the planet. Premieres Mon, Jan 4 at 10/9c after Fast N' Loud.

Before you give your truck a fancy facelift, hear what The Muscle and Red Beard have to say about choosing headlights.

It's rugged. It's sleek. It's strong. And it was given away to a lucky Diesel Brothers fan!

While out delivering Patriot Tires, The Muscle falls in love with a 2015 Denali. Will his obsession with the truck hinder his negotiating skills?

Check out Chavis’s souped-up truck, The Reaper.

It’s a truck. It’s a camper. It’s perfect for excursions into the great outdoors.

Heavy D and Diesel Dave put the Grade 5 and Grade 9 bolts to the test against the shop press to see if they can handle the force needed for the helicopter build.

Looking to make a deal? Learn everything you need to know. Muscle to the rescue!

With a 12 inch lift and 40 inch tires, the Denali is ready for Shawna’s weekend adventures in the mountains.

With turned-up fuel tables in the ECM, you know this UTV is ready for anything Marshawn Lynch has in mind.

The sheet of UHMW was cut into a square for the roof. The custom roll cage is not a perfect square. It’s crunch time, so it’s time to get creative.

Marshawn Lynch wants speed, stance, and style. It’s up to Heavy D to figure out how to translate that into a dune-buggy UTV.

Diesel Dave and Chavis have to extract the Hummer’s power steering system to figure out why the belt popped off.

Heavy D and Red Beard meet Mountain Man, the illusive owner of a diesel-powered Hummer H1, with hopes of sealing the deal for a new giveaway build.

The team heads to the racetrack to test Chavis’s performance truck, The Reaper, before The Ultimate Callout Challenge.

The guys line up their best builds with the hopes that Chuck Norris falls in love with the Bro Dozer.

After consulting an Applied Physics professor (Heavy D’s brother!?) and adjusting the roll cage and weight distribution, the Somersault Truck is ready for its big debut.

Out with the old in with the new. The guys have to fabricate an all new roll cage for the somersault truck after learning the axial rotation was incorrect.

Because they’re giving away the Mega Ram, it needs to be reliable. The best option? A CNG Kit to boost power and efficiency.

The BroDozer is up for sale for $99,000, but Heavy D is hesitant about losing one of his favorite builds.

After working tirelessly on the MLB builds, it’s time to take a break, hop in some UTVs and get racin’.

While in Lakeland for Spring Training, Heavy D and Diesel Dave borrow a massive mud truck to show Carlos what it means to have a proper lift kit and durable suspension.

Diesel Dave and the Muscle pay a visit to Ken from Expressions Upholstery to give the National League UTV customized leather seats.

MLB Network Analyst and former MLB infielder Mark DeRosa takes competition seriously. Even if it means running over a cardboard cutout of himself in the new National League UTV.

The crew head for the slopes to decide which fan is going to win Heavy D's baby, the face of DieselSellerz, the MegaRam.

Steve Darnell and his Welderup crew comes in clutch as the tech inspection for the Mint 400 looms over the guys and the Ford F100.

A client calls in a request for better mileage and tow power for his daily driver with a $25,000 budget. Diesel Dave puts his skill to the test and takes the lead on the build.

Chavis and Diesel Dave install both radiators into the Ultimate Tow Rig to ensure the motor never overheats when it's towing a heavy load.

Pace and Ryan are just about finished fabricating the rotating turret seat so they let Muscle hop on for a spin to verify its safety and strength.

With a new coil spring suspension, a reworked rear steer system and two massive T-Shirt guns, the #SuperSix is ready to head to its new home.

Chet and Tyson are tasked with installing the new 6-inch lift for the Nissan and decide the instruction packet would be more enjoyable when put to tune.

Heavy D gets behind the wheel of one of the baddest monster trucks at Thunder Alley in Las Vegas.