2007.5-2010 GMC Duramax LMM Suspension Parts

How GM set up the 2007.5-2010 Sierra HD chassis

Every Sierra HD of this run, Work Truck through SLE and SLT, uses the same basic layout: torsion bars and upper and lower control arms in front, semi-elliptical multileaf springs in back. The staging differs by truck. A Sierra 2500HD got a two-stage rear pack, 35 mm twin-tube shocks and a 36 mm front stabilizer bar; a 3500HD got a three-stage pack, 46 mm monotube shocks and a 34 mm bar. Single-rear-wheel trucks could be ordered with Z71 Off-Road, which brought 36 mm twin-tube gas shocks, a 36 mm bar, jounce bumpers and skid plates. The axles are rated 6,900 lb at the rear on a 2500HD, 6,500 lb on a 3500HD with single rear wheels and 9,200 lb on a dually, with 4,800 lb up front, so a tired spring or shock usually shows up first in how the truck handles a load. The 6.6L Duramax ahead of all of it is the LMM.

What fails and why

Start with the rear. Hook a fifth wheel or drop a slide-in camper into a 2500HD and the two-stage leaf pack squats. The nose points up, the headlights go with it and the truck wanders. That sag is the most common reason a Sierra owner buys suspension parts. The front end is the other half. Leveling with cranked torsion bars or taller keys changes the front geometry, and ball joints, tie rods, idler and pitman arms wear faster once the truck has been raised. The tell is a clunk over expansion joints and tire wear that will not stay even between rotations.

Replacing versus upgrading

Decide by what the truck does in a normal week. A Sierra that mostly runs empty and rides rough wants fresh shocks in the stock valving range and nothing else. A truck that tows most weekends is better on a monotube or remote-reservoir shock that keeps control when the damper gets hot. If the load comes and goes, air helper springs beat a heavier spring pack, because you can put air in for the trailer and take it out for the commute. Add traction bars if the rear axle wraps under power, and upgraded sway bar end links if the body rolls more than it used to. A bracket lift changes tire size, driveline angles and steering wear all at once, so treat it as a project rather than a bolt-on.

What we carry

Air Lift covers the load side here: LoadLifter 5000 and LoadLifter 5000 Ultimate Plus helper spring kits, stainless steel upgrade kits, air spring spacers in two, four and six inch heights including angled versions, a universal spring cradle, air hose, replacement on-board compressors, WirelessOne and WirelessAIR tanks with EZ mounts, and load controllers. BDS Suspension handles the lift and traction side with bracket lift kits, fixed and Recoil traction bars, mounting hardware, an upper control arm kit and a skid plate for 4-6 inch BDS lifts. Wehrli Custom Fabrication lists 60-inch and 68-inch traction bars, bracket and hardware install kits and replacement bushings and heims. Damping is Bilstein, in B6 4600, B8 5100, B8 5160 and remote-reservoir form, front and rear. Merchant Automotive lists an off-road lower control arm bump stop kit and BD Diesel an upgraded sway bar end link set.

Fitment notes

Know your truck before you order. A Sierra 3500HD was built with single or dual rear wheels, and the dually is wider at the rear, so bags, bars and shocks are not shared across the two. Wheelbase ranges from 133 inches on a regular cab long box to 167 inches on a crew cab long box, and some BDS kits are written for 2WD or for 4WD only. Everything on this page belongs to the 2001-2010 independent-front-suspension group. The 2011 refresh replaced the frame, control arms, torsion bars and leaf springs, so parts do not cross that model year. Helper spring kits listed for a Sierra 1500 do not fit a Sierra HD. On an already-lifted truck, air springs need the matching spacer kit to reach. And a steering brace that supports the pitman and idler pivots cannot be used with a lift that drops the center link. When in doubt, verify by VIN or run the fitment checker.

Frequently asked questions

Does a Sierra 3500HD use the same rear springs as a 2500HD?

No. The 2500HD came with a two-stage leaf pack and the 3500HD with a three-stage pack, and the shock and stabilizer bar sizes differ too. Dual-rear-wheel 3500HD trucks are a third case. Order by the truck on your title, not by the body style.

Can I put a BDS lift on a two-wheel-drive Sierra 2500HD?

Some of these kits are written 2WD-only and others 4WD-only, so read the listing. The seven-inch kits in particular are split that way. Check the drivetrain line on the product page, or call and we will pull the right part number.

Do I need traction bars on a Sierra HD?

Only if the rear axle is wrapping the leaf springs under power, which usually shows up as a hop or a bang on hard launches. Traction bars tie the axle to the frame to control that. We list fixed and Recoil style bars plus the brackets and hardware to mount them.

Will air bags raise my Sierra?

Helper springs are for carrying load, not for lift. They keep the truck level when a trailer or camper is on it and let you air back down when it is off. If you want permanent ride height, that is a leveling or lift kit decision, and it comes with the front-end wear tradeoffs above.

Not sure what fits? Call the shop at the number in the header, or use the fitment checker on any product page. We install everything we sell.