GM was the first manufacturer to offer independent front suspension on a full-size four-wheel drive pickup with the introduction of the GMT400 body style back in 1988, and that upgrade was included on the ½, ¾, and 1-ton trucks. To this day, General Motors still use IFS across their entire pickup line, even though Ford and Ram stuck with the more traditional solid front axle for their heavy-duty trucks. While there’s no disputing the fact that a solid axle takes the win in the overall strength and durability department, the older design can leave a little to be desired in the ride quality and handling area, so at first, IFS seemed like a great idea. Independent suspension allows each wheel to react to changes in the road surface without affecting the wheel on the opposite side of the truck, which leads to better handling and a smoother ride, plus the amount of un-sprung weight is a fraction of what you get with a solid axle. Win-win, right? Not so fast… Critics of IFS are quick to point out there are more moving parts to wear out, as well as some inherent design flaws which can lead to broken parts more frequently than with a solid axle design, especially in the case of GM’s 2500 and 3500HD trucks made from 2001 and newer.
A Typical Scenario
The biggest weakness of a GM 4×4 IFS setup is actually not in the suspension itself, but rather in the steering linkage. When you’re operating in 2wd and there is no power flowing through the front axles everything is fine, but as soon as you shift into 4wd and apply power, the problems begin. Because of the geometry built into the suspension and steering, the front wheels naturally want to toe in toward each other as torque is increased, and it’s up to the tie rods, center link, pitman arm, and idler arm to resist this force and keep the front wheels pointed straight ahead. In “normal” 4wd operating conditions like ice, snow, or light mud, usually the stock parts will do their job just fine on a bone stock truck, provided you’re not too aggressive on the throttle, but in the real world, things aren’t so simple.
Let’s say its Friday night, you’re with some friends, and you’re using your truck as an enthusiast does. There is a trail next to your house you’ve been anxious to try out, and tonight is a perfect night for a little off roading. Towards the end of the trail things get a little trickier, and you wind up climbing a rocky hill. It’s a little steeper than you thought, but your brand-new Ridge Grapplers have plenty of grip, so the rocks and dirt are no match for the horsepower of your Duramax. Towards the top you begin to lose a little momentum, and normally most problems like this can be solved with a little extra horsepower, but in this case, that can actually create a few more problems. As soon as you stand on the throttle, the turbo spools up, the tires begin to claw at the dirt, and the truck start to gain a little momentum. Things are going great, but a little bump in the trail causes the front end to pop up just a little more than usual, and as the suspension compresses back down again, the truck lurches violently side to side and suddenly you have no control over the steering. As you hop out and inspect the damage, the first thing you notice is both front wheels are pointed sharpy towards each other, and you’re calling for a ride home. Welcome to the Duramax owners club. The fee for admission? It starts with a new set of tie rods.
Here’s the deal: the stock steering linkage simply isn’t designed to take the abuse your Duramax can dish out. The tie rods are by far the weakest link, but they’re followed closely by the center link, and finally the pitman/idler arms. It’s important to note if you’ve leveled or lifted your suspension the steeper angles can cause much more stress on the steering parts, but the wheels you run can also have a HUGE impact on the steering parts as well. Stock rims always have a high positive offset (usually +20mm or more) which means the center of the tires are very close to the pivot point of the spindle and ball joints, and it requires very little force to turn the wheels side to side. On the other hand, the aftermarket deep dish wheels we all love to run have a negative offset (-12mm, -24mm, -44mm and so on) and they push the centerline of the tire much further away from the pivot point of the steering knuckle. Combine this with a heavier off-road tire, and now it takes a lot more force to just turn the wheels, but it also means the natural toe in effect as torque is applied is amplified many times. Simply put, deeper dish wheels and wider tires put a lot more stress on an already marginal front steering system and increase the likelihood of breaking parts.
The Solution
The first thing I’ll say, is when (not if) you break your first set of tie rods on your Duramax HD, don’t go to the local parts store and buy a stock replacement unless it’s just a temporary “get you back to work on Monday” type of solution, because you will be guaranteed to break those just as easily as the stock ones. There’s no sense in a band-aid fix, and even if your truck is 100% bone stock, you really should consider an upgrade, ideally before you are stranded in the woods. There are a ton of options to choose from to beef up your Duramax steering, and the costs can go from a little to a lot, so what options should you choose? The answer to that depends a lot on how you use and have modified your truck. For the vast majority of Duramax owners, a typical modification list will include a leveling kit, slightly offset wheels, tires that are a couple sizes larger than stock, and some sort of power upgrade like a programmer, exhaust, and an intake.
BD Diesel has been manufacturing parts for diesel pickups for a very long time, and if you want to increase the horsepower diesel, they have everything you’ll need from turbos to transmissions, but what you may not know is they also have upgrades for your steering and suspension as well. Whether you’re pulling a trailer through a field, pushing a snowplow, or just having a little fun off road, BD’s Heavy Duty Tie Rods are just the ticket. The body of the BD tie rod is 50% thicker than stock which substantially increases its stiffness, making them resist the force of the front wheels trying to toe in, plus the inner ball joint is larger than stock, which means they will last much longer than parts store replacements before they wear out.
One great thing about the stock tie rods, is they act sort of like a fuse and protect the rest of the steering components, but once the tie rods have been upgraded, you will easily find the next weakest link in the chain, and that’s the center link. Usually it won’t snap in half, but I’ve bent one or two on a boosted launch, but thankfully BD Diesel offers a solution for that as well. If you opt for their complete Heavy Duty Steering Upgrade Kit you’ll get the HD tie rods, but also their center link which is 30% stronger than stock, and it also comes with longer and stronger sway bar end links which are necessary for a leveled truck. The great thing about the BD Heavy Duty center link and tie rods is they use the same geometry and attachment points as stock which means no changes to your trucks handling characteristics or your turning radius, and the kit bolts directly in with zero modifications, giving your truck a much stronger steering setup for only $450.
To the Extreme
If you’re planning on piloting your Duramax in a competition type environment like sled pulling, drag racing, or just abusing it off road, there are a couple more steering upgrades you should consider. Sled Pulling for example, is about the most destructive thing you can do to your steering parts on a Duramax, followed closely by drag racing and 4wd boosted launches. Of course, if you have a lot more horsepower than stock, your steering problems are only going to get worse, and when you combine things like big turbos, full throttle off-roading, thick mud, rocks, and of course deep offset wheels and massive tires, you’ve got a recipe for bent and broken parts.
Kryptonite is a well-known name when it comes to bulletproof steering, and that’s because they’ve earned a reputation for building some of the strongest steering components available for your Duramax. With their help, you can upgrade every single moving part in your steering linkage and never have to worry about breaking anything again. Depending on your budget, you could slowly piece a system together over time, but because of how much work it is to replace each individual part, I usually recommend just jumping into the deep end and grabbing their Ultimate Front End Package and knocking it all out at once.
The kit comes with their SS Series Center Link and Death Grip Tie Rods, an Idler Support, an Idler Arm, a Pitman Arm, and their weld on Idler Support Frame Gusset. Here’s the breakdown: The Death Grip Tie Rods are built from an inch and a quarter hexagonal material and can withstand up to 21,000lbs of force, making them invincible in the roughest conditions. The stock center link has a curved section on each end which makes a weak spot, but the Kryptonite SS Center Link is made from a thicker and stronger material, but because it uses a different inner ball joint design for the tie rod, they are able to eliminate the kink from the factory center link while still maintaining stock steering geometry and handling characteristics.
From there, the next two parts we haven’t talked about yet are the pitman and idler arm. The stock pitman and idler usually won’t fail in a spectacular fashion like the stock tie rods will, but they can get twisted up pretty badly when a center link gets bent, or they’ll just wear out rather quickly from larger wheels and tires, and when they do, you’ll notice symptoms like excessive play or wandering in the steering wheel. To go along with the best tie rods and center link on the market, a Kryptonite Death Grip Idler Arm, Pitman Arm, and Idler Support will round out your upgraded steering system and will withstand the abuse of a high-power diesel, boosted launches, aggressive off-road driving, and more. The coolest thing about any Kryptonite part is they come with a no fine print, dare you to break it warranty which means no matter how you use or abuse the truck, if you can somehow find a way to break any Kryptonite part, they’ll send you a replacement free of charge.
Leveled the Right Way
On top of their incredibly strong steering parts, Kryptonite also has the products you need to properly raise the front end of your GM IFS truck as well. A leveling kit isn’t about increasing the strength of your front end because the factory suspension parts are pretty strong already, but if you want to raise your front end, the stock control arms can reach the limit of their travel range, so you need to make a few corrections to the ball joint angle and to the up-travel limit designed into the upper control arm. Kryptonite’s “Stage Two” leveling kits come with the torsion bar keys needed to raise the truck, as well as new upper control arms which will correct the ball joint angle and restore your up-travel you lose when you crank the front end of your GM pickup. This means you don’t get the harsh ride sometimes found on a leveled IFS truck. The Stage 2 kit comes with spacers that allow you to re-use your stock shocks, but if you want to improve the on and off-road ride quality even further, their Stage 3 kits come with Fox 2.0 shocks not just for the front, but for the rear of the truck as well. You can use their leveling kit alone or in conjunction with their Death Grip steering kits, depending of course on your needs and how you use the truck.
One final upgrade worth mentioning if you’re fixing up the steering on an older truck is the steering gear box itself. Stock boxes wear out which means excessive play, or they’ll just leak, and normally you’d just go to the parts store for a replacement. However, most of the time, the remanufactured gear boxes you get from the local parts store aren’t rebuilt to the highest level of precision, and they usually have more play than the worn-out stock box you’re replacing. For a true upgrade and to tighten up the steering the right way, a Redhead steering box is the go-to solution. They are carefully remanufactured with custom sized internal parts to eliminate play and wandering, and they’ll last a lot longer than stock as well.
Facts of Life
Regardless of which brand of truck you choose, there will always be some shortcoming in its design, whether it’s the transmission behind a Cummins, the injection pump on your Powerstroke, or the steering on your Chevy. As we modify our trucks, we can quickly find the weak link in the factory parts, and the GM IFS steering parts are no different. Sure, they are way underbuilt from the factory, but luckily there is a strong aftermarket that supports our passion and offers solutions for just about any problem you will encounter. All you gotta do is get out your credit card, roll up your sleeves, and spend a couple hours in the shop, and you can eliminate all your steering problems once and for all with a few carefully selected parts. After that, you’ll be able to keep the front wheels pointed in the right direction no matter how hard you stand on the throttle.