DJM 4/6 Lowering on a 2010 GMC Sierra
Shorty Got Low
The sport-truck movement is still alive and well. Here at Truckin, we are big supporters of taking standard cab trucks and making them sit lower and look as mean as possible—with the added bonus of making them handle better and stripping their boring stock looks. It’s a blessing and curse for us really. When we see a truck out on the road, our initial thought is to start sizing it up for improvement, and the first areas we look at are suspension height, as well as wheels and tires.
It was only a natural progression when Street Rodder’s Rob Fortier came wandering through the Truckin offices flaunting his un-altered ’10 GMC Sierra, we knew this red rocket was destined to get a series of upgrades. In our mind’s eye, we already had the Sierra sitting lower to the ground with a set of tastefully larger rollers and meats to compliment the drop. And we already had in mind what we were going to use.
The idea was to take this modern-day sport truck of a ’10 GMC Sierra 2WD standard-cab shortbed, and give it a little bit of attitude, along with the just-right stance, which a 4/6 lowering kit from DJM Suspension can offer. For this particular kit, DJM sent us a set of tubular steel upper and lower control arms that work with the factory struts to bring the front end down 4 inches. The rear consisted of a leaf-under-axle flip kit that uses the factory leafs with the DJM Axle Flip brackets. All the brackets and flat plates are plasma cut, all joints are MIG welded, and every bit of this DJM kit was made right here in the USA. The components themselves were treated to an immediately recognizable hammer-finish powdercoating color scheme that graces almost every part that leaves DJM’s hands.
It almost seems natural to have a standard cab shortbed this low to the ground and give it a larger set of wheels and tires to roll around on. After all, this GMC can trace the first sport truck back in its lineage, and these ’07-’14 series are no stranger to the custom world, having seen every incarnation of aftermarket upgrades come its way. We finished off the low look a set of fully polished 22x8.5 and 22x10 US MAG Milner wheels with 265/40R22 and 285/40R22 Falken ZIEX S/TZ tires. They were mounted and balanced by our pal Beto at New Year Wheels, Tires & Powder Coating in Santa Ana, California. Finally, we went a step further and installed a brand-new driveshaft from Inland Empire Driveline in Ontario, California. Follow along as we lower this ’10 GMC Sierra with a DJM 4/6 kit in the TEN Tech Center.
The front lowering kit consists of the steel upper control arms with their adjustable ball joints, tubular lower control arms with ball joints ready to install, cam lock plates and sway bar endlinks. All eight of the sleeves on the quartet of arms have been factory drilled for zerk fittings to make greasing that much easier.
The rear kit comes complete with upper and lower axle brackets, spring plates, new bumpstops, U-bolts and new left and right hangers. All brackets and flat plates have been skillfully plasma cut and coated with the same telltale hammer-finish powdercoating. This kit came with a set of drop shocks, too.
We removed all four tires and were faced with these peculiar little gadgets attached to the coil springs by a previous owner. These coil spring clamps were used to lift the spring by stretching it. For this application, they added about an inch of lift. We wasted no time removing them and tossing them in the scrap pile.
Turning our attention back to dismantling the front brakes and hub, we pulled the ABS line from its clamp and removed the brake line from its clamp on the arm.
As a newer truck and from the West Coast, the control arm nut was buzzed out with no problem. A quick whack with a hammer, and the arm was removed from its home on the spindle. At this time, we also removed the brake caliper and hung it out of the way.
The sway bar endlinks were next, which also came out with no issue. Once free, we rotated the sway bar up and out of the way. We would be replacing the endlinks with new ones from the kit.
Our first snag came when we attempted to loosen the lower control arm bolt and free the U-joint from the spindle. The U-joint was stuck good. We hit it with a pneumatic-powered pickle fork, and even then, it held steadfast. We had to use a combo of hammer blows and the fork to get it to release. The upper ball joint released just fine, and we removed the spindle and set it aside.
Only thing left holding the upper and lower arm together at this point was the strut. We buzzed out the lower bolts, and left the uppers in because we are not removing the strut, just replacing the arms themselves.
We were able to loosen and remove the pivot bolts on the lower control arm. Removing the arm from its factory location took a little bit of force, but it came out, and we immediately threw it into the scrap heap. It will be replaced with the new lower arm from the kit.
The upper control arm, the smaller of the two, was removed in similar fashion. We removed the pivot bolts and yanked it free. Seemed like a shame to toss away almost new parts like this, but in order to get our Sierra lower, it had to be done.
Both the upper and lower arms came to us from DJM with pre-drilled holes in each of the mounting sleeves, ready to receive a zerk fitting to make greasing the inner polyurethane bushings easier once installed. We worked on the lower arm to install the delicate fitting.
Each bushing received a metal crush sleeve lightly coated in grease. The crush sleeves are slightly longer than the bushing and designed to prevent over-tightening and smashing of the bushing, allowing the control arm to rotate smoothly.
Next, we filled the grease fittings. It only took a few pumps, but it gave us piece of mind that we could repack the grease at any point later on as needed.
We installed the upper arm’s 1-inch ball joints, which also had pre-drilled holes for zerk fittings. These were carefully installed and filled, as well.
With the upper arm prepped, we installed it into the factory location. We installed the cam lock plates in the center position and tightened to 40lb-ft.
We installed the lower arm, which went in similarly to the upper. We slid the arm in and bolted it up loosely.
Using a transmission jack, we reconnected the spindle to the upper and lower control arms. We attached the lower strut bolts to the lower arm, bolted back the steering arm, and reattached the brake caliper. The new sway bar endlinks from the kit were bolted to the sway bar, and with that, the front installation was done.
Moving to the back, we were ready to install the rear flip kit. Using a pair of jackstands, w loosened and removed the stock rear leaf spring bracket, and removed the U-bolts. We also removed the brake lines from their brackets to leave the axle free to swing around, if we needed to move it.
While we in that area, we removed the rear shocks. We had to free up the axle to install the flip kit, and we were replacing the shocks with new ones from the kit.
With the shocks removed, we had more room to remove the bolt holding the leafs together. We spayed a fair amount of penetrating lube into the bolthole, clamped the leafs together, and removed the bolt using our vice grip. The DJM kit provided a pin to install where the factory bolt had been.
We worked on the passenger side because it was easier to move around in. We unbolted the leaf from the hanger in the front and the shackle in the back, and with the shackle still attached, removed the leaf all together. On the driver’s side, we just unbolted the shackle and dropped the leaf still attached to the hanger, so we wouldn’t have to drop the gas tank.
Shop manager in the TEN Tech Center Jason Scudaleri was on hand to lend his plasma torch skills and cut off the factory bumpstops. We would be drilling and tapping a hole for the new bumpstops from the kit.
This is what was left of the factory bumpstops after they were torched off. The slight shine left over is the factory chassis coat that has melted away. Believe us, that stuff gets everywhere when it’s in liquid form, and we had to put down a ground cover to catch the drips. And the gas tank is on the driver’s side, right near the bumpstop. We were extra careful and used a shield to handle the sparks.
We reinstalled the passenger leaf to the hanger and wrapped it under the axle and up to the rear shackle. We slipped in the lower axle bracket, aligned it with the upper bracket, and bolted it in loosely. We did the same on the driver’s side. Our rear flip kit was starting to take shape. We hung the U-bolts to give us a sense of where their final location would be.
We locked in the axle bracket and went to work on the U-bolt bracket, positioning it in line with the U-bolts and tightening it down. There was no need to cut off the excess bolts; they did not stick down far enough to present a problem or interfere with anything.
We had cut off the bumsptops earlier and had to drill a new hole to install our DJM-provided new bumpstops, which were significantly shorter.
With our hole drilled nice and square, we took the tap that came in the kit and painstakingly cut in some new threads to seat our new shortened bumpstop. The angle is bad and required a lot of quarter turns and backing out, but we got those threads cut pretty quickly.
With all the suspension components installed and torqued down, all that was left involved reattaching the brake line brackets and installing the new rear shocks. Our DJM 4/6 kit was complete!
For the final polish, we travelled over to New Year Wheels, Tires & Powder Coating in Santa Ana, California, to have these 22x8.5 and 22x10 US MAG Milner wheels with 265/40R22 and 285/40R22 Falken ZIEX S/TZ tires mounted up.
The New Year crew made short work of our U.S. MAGs and Falkens.
As a full-service shop, the New Year crew had our wheels and tires balanced in no time flat. We loaded our new, shiny wheels back into the Truckin shop truck and got back to the Tech Center to mount up our dynamic duo.
DJM has made provisions so that the factory driveshaft fits without being too long and damaging the transmission. We decided to take that preventative maintenance one step further by having a new driveshaft designed and built by Inland Empire Driveline Services in Ontario, California.
Not bad for a few days work! Our Sierra had the right sport-truck height, thanks to the DJM lowering kit, and had the right look in the wheel department with the U.S. MAGs and Falkens. This red rocket had enough low to make anyone happy!
DJM SuspensionGardena, CA 90248
Falken TireFontana, CA 92335
Inland Empire DrivelineOntario, CA 91761
New Year Metal FinishingSanta Ana, CA 92705