In the last installment of our project, we walked you through the process of installing a new set of lower-ratio axle gears. The new gears would allow us to run a larger-than-stock tire while keeping engine rpm in its happy place. This month, we’re going to install a Fabtech 8-inch lift kit, which will provide the room needed to place our intended 37-inch tires under the 2007 Chevrolet Silverado 3500HD.
The Fabtech 8-inch Performance System utilizes cast one-piece steering knuckles; heavy-duty, high-arched lower control arm crossmembers; and tubular upper control arms to produce the desired amount of lift while retaining the factory torsion bars and keys. For better comfort when the road gets rough, we chose to go with the dual, 2.25-inch-diameter Dirt Logic reservoir shock option for the front, with a single shock at each corner in the rear. Continuing the quest for a more comfortable ride, we chose to sacrifice a small amount of payload capacity with a set of 6-inch-lift (for a level stance) long-travel leaf springs from Atlas Spring.
For the installation, we headed down to Bud’s Diesel in Midway City, California, where two of its best technicians knocked it out in no time at all. Overall, the kit was pretty straightforward to install aside from a bit of cutting and welding. When installed, it provided enough clearance for 37-inch tires with only minor trimming of the front bumper. In the end, we were quite pleased with both the Fabtech lift kit and the meticulous attention to detail and hard work from the guys at Bud’s Diesel.
With the axles geared and the lift complete, we’ll be hitting the dyno for our next installment, working to add more power to our already mighty Duramax engine. Stay tuned!
| 2007 Chevrolet Silverado 3500HD Teardown Details
We are once again going to skip all the boring teardown details and get straight to the good stuff. With the factory suspension, fender liners, and front differential removed, the techs at Bud’s Diesel were ready to begin the installation of the Fabtech 8-inch Performance Suspension system.
| 2007 Chevrolet Silverado 3500HD Differential Drop
To provide the clearance necessary for the differential drop, a portion of the rear lower control arm mount on the driver side was removed. Greg Nelson made short work of this task with a reciprocating saw and a steady hand.
| 2007 Chevrolet Silverado 3500HD Protective Black Paint.
Once the material was cut off, Neil Fabula showed off his welding skills by installing the provided gusset plate. The plate was then allowed to cool before receiving a coat of protective black paint.
| 2007 Chevrolet Silverado 3500HD Differential Housing
The reciprocating saw came out once again as Nelson carefully guided it through the delicate aluminum of the differential housing.
| 2007 Chevrolet Silverado 3500HD Differential Housing
To work with the drop brackets, a new mounting bracket is provided and the factory upper mount is removed for clearance.
| 2007 Chevrolet Silverado 3500HD Rear Heavy Duty Lower Control Arm Crossmember
Before the differential could be hoisted into place, the rear heavy-duty lower control arm crossmember was bolted in. Made from ¼-inch steel, this burly unit required the strength of both of our technicians.
| 2007 Chevrolet Silverado 3500HD Differential Housing
Next, Nelson and Fabula bench-pressed the heavy differential housing into its new home.
| 2007 Chevrolet Silverado 3500HD Front Crossmember
With everything left loose, the guys slung the front crossmember into place in the lower control arm pockets, making way for the control arms to be reattached.
| 2007 Chevrolet Silverado 3500HD Lower Control Arms
Now that the lower control arms were in place, the two crossmembers were tied together and all the bolts could be torqued to spec.
| 2007 Chevrolet Silverado 3500HD Bumpstop Relocation Bracket
A bumpstop relocation bracket is included with the kit, which moves the factory jounce bumper into the proper location for the truck’s new height.
| 2007 Chevrolet Silverado 3500HD Ubular Upper Control Arms
The Fabtech 8-inch suspension system comes complete with new tubular upper control arms, which are fitted with heavy-duty ball joints. These control arms align to factory specifications and include provisions for running the company’s dual shock kit.
| 2007 Chevrolet Silverado 3500HD One Piece Cast Knuckle
In addition to the lower control arm drop brackets, the Fabtech 8-inch system uses a one-piece cast knuckle to achieve the desired amount of lift. Fubula bolted the factory hub and brake assembly to the new knuckle before installing them on the truck.
| 2007 Chevrolet Silverado 3500HD New Knuckles
Due to the size and weight, hanging the new knuckles proved to be a two-person job, which Fabula and Nelson handled with ease.
| 2007 Chevrolet Silverado 3500HD Dual Shock Option
Since we opted to go with the dual shock option, which mounts to the upper control arm, the kit included a pair of tubular-steel shock hoops. The hoops utilized an existing frame and control arm bolt, along with four new bolts, which were drilled into the top of the upper control arm mounts.
| 2007 Chevrolet Silverado 3500HD Tie Rods
No GM HD lift kit is complete without a set of beefed-up tie rods—and Fabtech provided some of the burliest we’ve seen yet with this kit.
| 2007 Chevrolet Silverado 3500HD Fabtech Dirt Logic Racing Shocks
A pair of 2.25-inch Fabtech Dirt Logic racing shocks graces each corner of the front suspension, along with a pair in the rear. These remote reservoir shocks have what it takes to keep the suspension under control when our heavy truck hits rough roads. They certainly look good as well.
| 2007 Chevrolet Silverado 3500HD Lower Differential Mounting
A longer front driveshaft is necessary to accommodate the new, lower differential mounting location.
| 2007 Chevrolet Silverado 3500HD Front Driveshaft
Fortunately, one is provided with the kit and features a double-cardan joint at the transfer case for vibration-free operation.
| 2007 Chevrolet Silverado 3500HD Tubular Steel Impact Struts
Tubular-steel impact struts are provided to help strengthen the suspension drop bracket assembly. The struts connect the rear lower control arm crossmember to the factory transmission crossmember.
| 2007 Chevrolet Silverado 3500HD Torsion Bar Crossmember
Because this suspension system retains the factory torsion bars, drop brackets were installed to lower the torsion bar crossmember into the correct position.
| 2007 Chevrolet Silverado 3500HD Drop Brackets
Once installed, the stock torsion keys and bars were reinstalled.
| 2007 Chevrolet Silverado 3500HD Leaf Springs
Lifting the rear of the truck was as easy as replacing the leaf springs. We opted to use a full replacement spring pack from Atlas Spring instead of using a more traditional steel block. While these springs will sacrifice a little bit of payload capacity, our 1-ton truck will ride much nicer, and our kidneys will thank us.
| 2007 Chevrolet Silverado 3500HD Atlas Springs
Teamwork is key when working on big trucks. Fabula and Nelson carefully threaded the new Atlas springs into position, beginning with the front mount first and finishing with the rear shackle.
| 2007 Chevrolet Silverado 3500HD Extension Brackets
Rounding out the kit are extension brackets that lower the factory rear bumpstops, making up for the difference in height and ensuring no damage is done to the rear end at full bump.
