Vehicle Maintenance - Prep Your 4x4 - Moab Tech

Differential fluid will often have a metallic color to it as a result of the metal gears constantly meshing inside the differential. Not to worry, this is normal wear, but you do want to inspect for small pieces of metal, indicating that there might be a broken tooth, and also carefully look at the gears for visible damage like cracks.

The differentials are generally the lowest part of the vehicle and will often have a few scrapes that may offer an uneven surface when trying to reseal the cover to the axlehousing. Gently tap the surface with a smooth-faced hammer to ensure the best possible surface to seal the differential covers on the axlehousing. Be sure to tap down any irregularities and clean the surface of old sealant, grease, oil, or dirt before sealing up the differential.

Silicone sealant, or RTV, works great for a one-time seal, but the new, reusable LubeLocker differential gasket is recommended to properly contain the fluid that will be added.

Here is a broken electrical connection that's been keeping the rear locker from engaging. With the differential cover off, now is an ideal time to make repairs. The connecter that will be used is a water-resistant connector made specifically for exterior automotive use.

The wheels were removed to inspect the brake pads, calipers, and rotors to ensure proper working tolerances. The brake pads are below 50 percent and will be replaced in the front. The rotors show no irregular wear, and inspecting the calipers shows no brake fluid leakage. The Warn locking hubs were taken apart to be cleaned and inspected, and even after years of mud bogs and water crossings were found to be in perfect working order.

U-Joints endure an incredible amount of stress, and failure can lead to costly replacement of broken driveshafts, axleshafts, and pinion gears. Check all U-joints for any play by moving the joint in every possible direction while feeling for smooth fluid motion. Grinding or roughness in the joint means damage and the joint should be replaced. The front Dana Spicer U-joints have been through three years of trail abuse and have some side-to-side play, so they will be replaced with CTM greaseable U-joints that carry a lifetime breakage warranty. The factory axles are showing some twist and are being replaced and upgraded to Alloy USA axleshafts that are known for off-road durability and are a perfect match to install with the CTM U-joints.

The rear driveshaft was inspected and found to have some minimal play that was not noticed while driving. The drive yoke was slightly stretched from a prior U-joint trail fix, and it now gets replaced before it causes premature wear on the U-joint and a potential failure. Taking the U-joint straps off, one of the straps was found to have been overtightened to the point of being stripped and needs to be replaced. If overlooked, something as simple as this would leave the U-joint loose and eventually lead to a damaged U-joint and possibly a broken driveshaft. Installing the new yoke that fits snug enough to hang from the U-joint and being careful to torque bolts to the manufacturer's specifications will ensure longevity and keep repairs to a minimum.

If you have boots covering the shafts on your shocks, pull them up to check for any fluid leakage. If there is a fair amount of oil shown on the shaft, it means it's time for some new shocks. The Rubicon Express remote-reservoir shocks look clean after 20,000 off-road miles and will be left in place to enjoy out on the next trail.