One of the biggest advantages that the GM 2500 and 3500 HD trucks have over the other heavy-duty trucks in the category is the smoother and more precise-handling independent front suspension. Of course, the solid front axle found on the Ford and Ram counterparts is a more bombproof design, but if you’re looking for a good ride over a rough surface on a daily-driven 4x4, then IFS is usually the way to go. Unfortunately, modifying an IFS suspension for bigger tires is quite a bit more complicated than lifting a solid-axle 4x4.
With all of this knowledge in hand, JD Fabrication set out to level the stance of the 2011 to current GM HD trucks while improving the ride with 2 inches more wheel travel up front and tunable 2 1/2-inch King free-bleed bypass reservoir shocks at all four corners. The lift is designed to allow fitment of true 35x12.50 tires on the stock aluminum GM 18-inch wheels with only minor trimming. Installation requires slightly more than your common handtools, but no welding is required and you can do it in your driveway, followed up by a trip to the local alignment rack.
The JD Fabrication mid-travel kit for 2011-to-current GM HD front suspension starts with fabricated upper A-arms made from laser-cut, MIG-welded mild steel. The design of the arms allows for 2 inches of lift via cranked or keyed torsion bars and 2 inches of additional suspension downtravel.
Instead of a traditional ball joint, the JD Fabrication A-arms feature custom high-misalignment EMF uniballs. They are completely rebuildable, and no drilling is required for A-arm installation. The tapered shank matches the tapered hole in the factory GM knuckle.
OE-style rubber bushings are utilized on the frame end of the JD Fabrication A-arms. This reduces the amount of noise and harshness transmitted through the suspension and frame into the cab. These bushings are designed to last 100,000 miles or more and don’t squeak, rattle, or require any maintenance like some aftermarket alternatives out there.
The 2 1/2-inch King shocks included with the kit feature JD Fabrication–spec valving and special offset lower mounts to clear the CV 4x4 axleshafts. The free-bleed bypass tube allows for position-sensitive adjustment that you can tune to your liking. Turning the bypass screw firms up the suspension compression and rebound; loosening the screw softens the compression and rebound.
The factory front shock towers need to be modified to accept the larger King free-bleed bypass shocks. JD Fabrication includes a bolt-in circular jig to align a 3-inch hole saw in the GM shock tower. Temporarily removing the plastic inner fenderwells makes this task much easier.
With the hole cut and the jig removed, you can then cut out the front portion of the original shock tower with a cutoff tool, an angle grinder, or another metal cutting device. This is really the only difficult to reverse part of the leveling kit.
When you are done trimming, the shock tower holes will be U-shaped like this. JD Fabrication laid down some black spray paint to prevent corrosion. If you live in a rusty climate, you may need to primer and coat the area more carefully.
The JD Fabrication front upper shock mount bracket is a bolt-on piece. It’s cinched in place with Grade 8 fasteners and features a built-in mount for the shock reservoir. All hardware needed for installation is included with the leveling kit.
With the shock bracket bolted to the top of the shock, you can then insert the shock behind the A-arm. You can also install the shock and mount prior to installing the A-arm. It fits both ways for ease of removal in the future.
Once both ends of the front shocks are in place you can reinstall the plastic inner fenderwell. It will need to be trimmed to clear the shock reservoir and hose. Industrial scissors, a razor knife, or a cutoff tool can be used to make a clean cut.
Only a small bit of material needs to be removed from the lower inner fenders and front valence to clear 35x12.50R18 tires on the factory aluminum GM wheels. An air saw is the best tool for the job here, but other cutting tools can be made to work.
The rear suspension remains the stock height. JD Fabrication offers King free-bleed bypass shocks with reservoirs for this application. They bolt into the stock shock mounts, feature JD Fabrication–spec valving, and are fully adjustable just like the front shocks via the bypass tubes.