Fix Your 2007-Present Jeep Wrangler Now - Wrangler WrongedPosted in How To: Suspension Brakes on January 14, 2015
If ever there was a Jeep that garnered incessant whining from many of its owners, it’s the ’07-present Wrangler and Wrangler Unlimited. A whole herd of new-to-Jeep owners expect these JKs to feel, drive, and perform like the economy cars and crossover SUVs that were traded in. That’s a lot to ask of a simple ladder-frame, solid-axle Wrangler. That’s not to say nothing could be made better on these Jeeps—far from it. However, the things we would fix and replace are more important than making sure we had the latest door seal or computer reflash. If that’s your sort of thing, head to the dealer and let the techs run the VIN on your Wrangler. There is sure to be at least one TSB update due on your Jeep. Instead, we focused on the things that will surface when you modify your JK Wrangler and take it off-road regularly. Read up and head off a failure at the pass, before it becomes a real issue on-road or out on the trail.
Nearly every lifted JK owner has experienced death wobble or a shimmy in the steering to some degree. Death wobble is a speed-specific shaking of the front wheels and steering system. It often starts out as a minor wobble in the 35 to 50 mph range and gets progressively worse. The only way to stop it at the moment is to slow down or speed up and drive through it. Multiple issues often cause death wobble, so you need to inspect the front end very carefully. Many people incorrectly blame the tires only and swear that rebalancing them fixes the problem. The fact is, out-of-balance tires only exacerbate the issue. Other people think that adding a steering stabilizer will correct death wobble. A stronger steering stabilizer might cover up the problem, at least for a little while, but it doesn’t fix the root of the issue: worn or loose parts. The components that typically cause death wobble on a JK are the same parts that cause it on nearly any Jeep. Worn ball joints, worn wheel bearings, a worn or loose front track bar, a worn drag link or tie rod, or a combination of several of these parts are typically the reason for death wobble.
The factory JK ball joints are notoriously wear-prone. We have seen some factory ball joints last fewer than 5,000 miles on a lifted Wrangler with larger than stock tires. Around a 10,000-mile ball joint lifespan is fairly typical for a JK on 35s that sees regular off-road use. Fortunately, there are several heavy-duty aftermarket ball joint replacements available. Dynatrac (dynatrac.com) offers extremely heavy-duty rebuildable ball joints, and Synergy (synergymfg.com) offers a traditional press-in ball joint that features a much more durable construction than stock. You can inspect your ball joints by supporting the vehicle on jackstands and grasping the tire and wheel at the 12 and 6 o’clock positions to check for slop. If you feel movement, have a buddy identify where the movement is coming from. It will be either be in the ball joint area or in the wheel bearings.
The ’07-present Wranglers feature unitbearing-style wheel bearings on the front axle. In stock applications, they can last as long as 100,000 miles or more. In more abusive large-tire applications, they may only survive 50,000 miles or less. They are not adjustable or rebuildable. You simply remove the old unitbearing assembly and replace it with a new one. If you are chewing through bearings regularly, you probably need to consider installing a larger axle assembly.
To inspect the steering linkages, track bar, and track bar hardware, have a buddy turn the steering wheel from left to right about 1⁄4-turn several times with the engine off. Look for slop and unusual movement in the steering and track-bar assemblies. Loose hardware should be torqued to spec, but inspect the boltholes to make sure they are not wallowed out. Damaged boltholes should be repaired. Sloppy tie-rod and track-bar ends should be replaced.
Owners of Wranglers that see regular heavy rock use with tires that are 35 inches or larger should seriously consider adding a ram-assist steering system.
Once you are sure everything else under the front end of the Jeep is tight and in good shape, inspect the steering stabilizer. If it looks like it is dented or has leaked its fluid out, consider upgrading to a more heavy-duty unit that can better handle the larger tires on your Jeep. The Fox (ridefox.com) adjustable ATS steering stabilizer is the most versatile unit available—It’s also the most expensive. Several suspension and shock companies offer less-expensive stabilizer kits.
Owners of Wranglers that see regular heavy rock use with tires that are 35 inches or larger should seriously consider adding a ram-assist steering system. Companies like PSC (pscmotorsports.com) and Howe Performance (howeperformance.com) offer bolt-on ram-assist kits for the JK. The ram does add some complexity to the steering system, but it takes a lot of stress off of the steering box. Steering-box sector-shaft failure is not uncommon on JKs with 37-inch and bigger tires. JKS Manufacturing (jksmfg.com) offers a kit that reinforces both the sector shaft and the factory track-bar bracket. This kit would be right at home on all JKs with tires that are 35 inches tall and larger.
The factory CV-style driveshafts found in the ’07-present Wrangler are great for eliminating driveline vibration, but they are not all that durable. They are not at all ideal for use with lift kits and regular off-road use where the protective CV boots can be torn and the thin, large-diameter tubes can be dented.
Adding lift and leveling kits as low as 2 inches can cause driveshaft binding in some situations. The two-door Wrangler will need a traditional U-jointed rear driveshaft with lifts over 2 inches or so. The factory front driveshaft may come in contact with other undercarriage parts at full droop, but we were able to keep the front ’shaft in our two-door manual-tranny JK alive for over 75,000 miles with different lifts ranging from 3 to 4 inches. If the driveshafts are overextended, the CV boot will tear. Once the grease in the joint is contaminated, you be lucky to travel 100 miles before the driveshaft ejects itself from the vehicle, taking out whatever else is in its path. J.E. Reel (reeldriveline.com) and Tom Wood’s Custom Drive Shafts (4xshaft.com) offer several standard- and heavy-duty bolt-on U-joint-style driveshaft solutions for ’07-present Wranglers. Custom versions are also available for those that have swapped-in axles.
The JK Wrangler axles are fairly durable. Unfortunately, way too many people think they need 37-inch tires on their Jeeps with stock axles. Standard JKs have a Dana 30 front axle and a Dana 44 in the rear. Rubicon models have locking Dana 44s front and back. All of these axles are virtually identical from the cast centersection out. Running 35-inch or larger tires and using the Jeep off-road regularly will generally result in a bent front axlehousing, among other things. We’ve even seen stock front axlehousings literally snap in half under normal non-abusive conditions. Any JK with up to 35-inch tires needs a front axlehousing upgrade. There are several gusset and truss kits available for both the Dana 30 and 44 factory front axles. However, we see these gusset kits as more of a bandage trying to cover up a bigger problem. Plus, adding the gussets to an already-bent front axle is a futile cause. Dynatrac offers a heavy-duty ProRock 44 housing with beefier axletubes, end forgings, suspension brackets, and a burly high-clearance modular iron centersection. The bigger reinforced parts are much better at holding up to even normal off-road use than the stock JK front axlehousing assemblies. All of your Dana 44 internals bolt right in. Both Dana 30 and 44 outer knuckle components and brakes can be reused on the Dynatrac ProRock 44 housing.
Internally, even the Rubicon Dana 44s have weaknesses. While the factory front and rear gearsets are strong, there are inexpensive imported aftermarket gears available that are difficult to set up. The heat treating and quality control of these gears is often inconsistent and unreliable at best. If it’s the cheapest gearset on the market with a lifetime warranty, it’s probably not worth the cardboard box it’s stuffed in. They may be more expensive, but we’ve had really good luck using genuine Spicer (spicerparts.com) ring-and-pinion gearsets when re-gearing axles.
The factory JK front axleshafts are anything but weak. However, when 35-inch tires get bound up in the rocks, the deep-geared Rubicon transfer case can tear them up. If you have problems keeping the steering axleshafts and U-joints alive in your front axle, consider switching to something like RCV Performance Products (rcvperformance.com) heavy-duty CV axleshafts. It’s a simple bolt-in upgrade that provides near 35-spline Dana 60 axle shaft strength.
You may have noticed a trend here. There are several mentions about tires bigger than 35-inches tearing up your stockish JK. Well, same is true with the electric lockers in the Rubicon axles. It’s been our experience that even 35s can, and will eventually take their toll on the factory electric lockers if used off-road regularly. Typically, the problems start with the lockers not locking and unlocking properly, or taking a longer than normal time to lock and unlock. Stepping into 37-inch tires will guarantee that the electric lockers will live a short life, unless you spend all of your Jeep time on the street.
Suspension and Undercarriage
In most cases, the stock JK Wrangler track bar and link suspension brackets are plenty sturdy. However, adding lift kits and larger tires increases the leverage placed on these brackets. Track bar brackets likely get the worst of it. Many suspension lift kits include bolt-on extensions that can eventually pull the welded-on brackets from the axles. This is very common on the rear axle. JKS Manufacturing offers a thicker replacement bracket, as well as a heavy-duty gusset that makes the track-bar mount on the axle extremely durable. The thin lower control-arm brackets take a beating on rough trails since they are some of the lowest points on the axle. Several companies such as JKS Manufacturing, Rubicon Express (rubiconexpress.com), and Synergy Manufacturing offer thicker replacements that need to be welded to the housing. We’ve seen the rear upper control mounts free themselves from the frame too, but it’s not overly common.
One universally common issue is with the rear JK suspension. When you remove the factory rear driveshaft to install a U-jointed CV-style driveshaft, you also have to rotate the rear axle housing upward for the correct pinion angle. This in turn causes the track bar bracket to bind (and eventually tear off). It also causes the coils to bind and the bumpstops to make contact in the incorrect locations. This problem is worse on the short-wheelbase two-door Wrangler than on the four-door Unlimited model. Several companies such as JKS Manufacturing, Rubicon Express, and Synergy Manufacturing offer replacement coil mounts and bumpstop pads, which need to be welded to the axle in the proper locations once the old mounts are removed.
Bumpers and Body
Of course we all despise the factory plastic blow-up bumpers. They get crushed, scratched, and even torn off way too easily for anyone that spends any amount of time on the trail. The good news is that there are a multitude of different aftermarket front and rear bumpers available to choose from. Pick the styling you like, and there are likely three companies that offer something similar. And if there isn’t, just wait a minute or two, there will be.
Most of the aftermarket spare tire mounts rattle to some degree, depending on your driving style. The original spare tire mount on the tailgate has caused many JK owners grief, too. Bumping the spare tire on a trail obstacle can result in a damaged tailgate and hinges. Most 35-inch tires won’t fit the stock mount and bumper without a spare tire mount extension. These extensions cause rattling that eventually leads to damage of your tailgate and the spare tire mount, even during normal street use. Off-road use will cause cracks to form in several areas. We came up with a low-buck solution to the problem when using 35-inch tires. If you deflate the tire, it acts as a shock absorber that keeps the tire from rattling and tearing the tailgate apart. Deflating the tire also allows it to fit in the stock rear bumper groove. Of course, you have to carry on-board air to refill the spare tire if you actually plan to use it.
Engine and Transmission
The 3.8L V-6 found in ’07-’11 Wranglers is a little bit of a slug in the porky JK. The later 3.6L Pentastar V-6 produces more than 80 additional horsepower over the older 3.8L. It makes such a big difference that we would have a hard time buying an older JK without the 3.6L. Both engines have had a few bugs. Older mid-mileage 3.8L engines have been known to use oil excessively in some cases. The 3.6L had some head issues early on. As far as mods go, there are plenty available for both, but in our experience, many of them can cause more headaches than they are worth. Do your research when looking to pump up your JK’s power output and select a quality company.
When installing larger tires on your JK with an automatic transmission, it’s a good idea to increase the transmission cooling capacity. Flex-a-lite (flex-a-lite.com) offers several different transmission oil coolers that fit the bill. A larger tranny cooler is an especially good idea if you plan to hit deep mud, big rocks, sand, or monster snow drifts. The JK’s NSG370 six-speed manual transmission is like a time bomb when combined with larger-than-stock tires and regular off-road use. Expect a lifespan of less than 100,000 miles if it’s operated by a ham-fisted driver. The NSG370 is also difficult to rebuild. If your manual tranny begins popping out of First gear, start saving your pennies for a factory overhauled or new transmission.