Fixing the lift kit on a 4×4 ain’t no joke. Make sure you have the right tools and the right knowledge. Do NOT try at home if you do not. Better to hire a professional to make sure it gets done right.
Altering the suspension on a truck looks super cool and is fun to have, no doubt. However, if not well-maintained, it can have serious consequences if not done right. Here are some maintenance tips for the 3 main areas of concern:
1) Ride and Suspension
Many first-time lifted truck owners don’t realize the ride penalty in going high. Not all kits are created equal, and a rough-riding rig can add to fatigue on long trips, make controlling the vehicle exhausting, and put wear on the truck itself.
Low quality shocks and generic or average tuning can lead to issues with the handling of your truck, such as vibrations, axle hop, and loss of suspension damping, which would lead to a more serious problem. Torsion bar twisting is an inexpensive method many people use to lift their truck, which may be OK for leveling, but it is not a true lift because it merely adjusts height of the truck in its suspension travel. Therefore, the higher you go with a twist, the less down travel you will have, causing shaky handling, such as skipping across the road imperfections, rather that soaking them up. On 4×4 vehicles, this also causes an issue because you could over-extend a CV axle joint on a truck that has excessive compression, but limited droop.
Spring and shock technology has come a long way in recent years. Reservoir shocks once reserved for high-end race trucks are now within reach of many truck builders. These damping units are easily tuned, adjustable for ride height, and are readily available from many high-end shock suppliers. Custom leaf springs, tuned to your vehicle and your needs, can easily be purchased from a few quality companies. Traction bars that locate the axle to the frame to reduce unwanted movement and axle hop are another way to tame the wildness in your suspension.
A major drawback to upping the tire size is getting power from your engine to the ground. Installing different-sized tires from stock will effectively change your truck’s gear ratio. With a bigger tire, the truck will feel like it is geared higher (numerically lower), which is great for highway cruising, but not for low-end grunt, off-the-line acceleration, or passing power.
To bring your truck back to stock performance, it is important to re-gear the truck accordingly. A simple calculation will tell you what gear ratio would get you back to your stock equivalent. The calculation is your new tire diameter, divided by your old tire diameter, multiplied by your old axle ratio, will equal your new axle ratio (new tire diameter/old tire diameter x current axle ratio = new axle ratio). For towing or performance, you would want the next gear ratio lower than the stock equivalent. So, if our ’95 project Silverado had 30-inch tires stock, and a 3.73 axle ratio, that calculation would tell us we need a 4.103 (which rounds off to the readily available 4.10) gear ratio to get us back to stock. The next lowest ratio from a 4.10 is the 4.56, which should be selected for towing and performance. Needless to say, we went with 4.56s on the Chevy. Because of the extra weight associated with off-road tires, we recommend always going with a performance-minded gear ratio for any tire size above 35 inches. And, keep in mind that 4x4s need both the front and rear diff re-geared to the same ratio.
When altering a truck’s suspension to make it higher, the vehicle’s frame and body is moved up and away from the differentials. This causes the driveshaft angles to become extreme, often causing bind, premature wear, and nasty vibrations. On lifted IFS trucks, the CV joints also become an issue, especially on trucks that have a wider track, and are lifted with a longer coil spring or cranked torsion bars. Many aftermarket lift kits provide CV spacers to move the stock axle outward, effectively lengthening it, but spacers aren’t necessarily the best answer for the long haul.
For leaf sprung, solid-axled vehicles, pinion wedges should be installed between the axle and spring pack to compensate for the driveshaft angle by rotating the differential housing up, making for a clean pinion angle on the differential side. Often, this is not as easy to accomplish with the transmission or transfer case side of the driveshaft, and your U-joint-style driveshaft is best tossed for a custom unit, using a double cardan or CV joint that can run smoothly at higher angles. Custom-length CV axles are also a better bet for any lift kit, especially those that offer increased wheel travel over stock, and recommend that spacers should be used in conjunction with stock axles. The last thing you want is to blow a joint in the middle of nowhere, especially on newer vehicles that have live front axles in place of traditional hubs, and have no means of disengaging the front axle.