Annual Jeep Inspection - Seasonal Service
Give your Jeep an inspection at least once a year
If you’re like us, you probably thrashed on your Jeep all summer long. You probably also did very little maintenance, unless something came apart like the Challenger space shuttle attempting a lift off. We give our Jeeps a really thorough looking over before every off-road trip. Even while on the trail, we keep an eye out for loose hardware, bent steering, and dinged driveshafts. And if we plan to drive the Jeep home after a trail day, we’ll give some of the more important systems like the steering, suspension, wheels, tires, lug nuts, and driveshafts a quick look before hitting the road. You should inspect and service your rig at least once a year. Here is what you should be looking at.
Replace or clean the regular stuff first. If you are off-road a lot, you should perform an oil change and replace the air filter more often than the traditional service intervals. Look for and repair any obvious issues like corroded battery terminals, frayed or cracked belts, coolant, oil, and exhaust leaks, and so on. If you frequently cross deep water, water can get into the engine wherever oil leaks out. If you’ve noticed a recent drop in oil pressure or a new noise that doesn’t sound quite right, this is the perfect time to take a closer look. Top off all the fluids, or flush out anything that looks contaminated. Make sure that the motor mounts are in good condition. Several companies, such as Daystar (daystarweb.com) and Prothane (prothane.com), offer heavy-duty urethane motor mounts that are less prone to failure than the stock rubber parts.
Transmission and Transfer Case
These components often leak, especially on older Jeeps. Seal them up as best you can. Check the fluid level, and inspect the fluid. If it looks milky, then it’s been contaminated with water and should be flushed. Inspect the breather lines to make sure they are not clogged. Run the breather hoses as high up as possible to keep them from sucking water during water crossings. If you can find one, install a locking dipstick on your automatic transmission, this will help prevent leaks at extreme angles and keep dirt and water out. Inspect hydraulic and mechanical clutch and shift linkages. Mechanical linkages are wear prone and are rarely serviced. Grease anything with a fitting. Give the transmission mount a once over. If the rubber looks cracked and broken, now is a good time to upgrade to a Daystar urethane mount.
If you’ve noticed a chatter when releasing the clutch of a manual transmission or if the clutch has been slipping, you might want to have the flywheel resurfaced and replace the clutch. Consider a heavy-duty clutch from a company such as Centerforce (centerforce.com).
You should be looking over your driveshafts after every off-road outing. Driveshafts with deep candy stripes, dents, or kinks should be replaced or retubed. Inspect the U-joints carefully. Purge out and wipe away the old grease if the U-joints have fittings. If they don’t have fittings, look closely at the seal areas. Red rust dust around the seals is a dead giveaway that the U-joint is dry inside and about ready to fail. With the Jeep in Neutral and the emergency brake set, grab a hold of the driveshaft and check for slop. There shouldn’t be any. Replace any worn components. Give the driveshaft slip joints only a few pumps of grease. Overfilling them can cause them to hydraulically compress and pop out the dust cap, or worse, split your transfer case in half when your suspension compresses quickly.
Check the yokes and U-joint hardware for damage and binding. A few bumps and scrapes are no big deal, but if the yoke and hardware look like a three-year-old attacked them with a sledgehammer and a grinder, then you might want to consider replacing the parts. Binding driveshaft issues should be addressed by limiting suspension travel with limit straps or control axlewrap with a traction bar. In some cases, switching to larger U-joints and yokes can remedy the problem. Look into switching from Spicer 1310 to 1330 or 1350 to 1410 if you need more driveshaft angularity. Tom Wood’s Custom Drive Shafts (4xshaft.com) offers a Super-Flex U-joint for Spicer 1310, 1350, and 1410 applications that allows even more driveshaft angularity.
Check the fluid level and flush out the housing if the fluid is contaminated with water or grit. Look for metal chips and chunks in the oil and on the magnetic drain plug if equipped. Some small metal particles are normal, large chunks could mean something is about to go awry in your axle, if it hasn’t already. With the transmission in Neutral and the parking brake set, grab a hold of the yokes and check for endplay. There shouldn’t be any. If there is, your axles will likely need to be rebuilt. If you pull the cover to drain the oil, you might as well throw some marking compound on the ring gear to check the gear pattern. And while you are at it, check the backlash with a dial indicator.
If your Jeep has bolt-on locking hubs, make sure the bolts are tight. Consider using thread-locking compound, or better yet, replace the bolts with studs and locking hardware. Check the wheel bearings and ball joints/kingpin bearings with the tires on the Jeep. Support the vehicle with jackstands and grasp the front tires in the 12 and 6 o’clock positions checking for slop. If there is movement, have a friend look to see where the movement is coming from. Worn ball joints and unit bearings should be replaced. Loose traditional wheel and kingpin bearings can be repacked.
Inspect the front axleshaft yokes, steering U-joints, and snap rings. Just like on a driveshaft, check the U-joints for rust dust around the seals. U-joints with no grease left should be replaced. If the U-joint snap rings are missing and the caps are working their way out of the yokes, you can temporarily fix the problem by tapping the caps back into place and tack weld them to the yoke. Ultimately, you have a problem, and you’ll eventually need to upgrade to something stronger like shafts from RCV Performance (rcvperformance.com). If the yoke bores are wallowed out enough that the caps rattle around in them, replace the shafts right away.
Fix any and all oil leaks on your axles. If oil can get out, water can get in. Just like on the transmission and transfer case, check the breathers for clogs and route the breather hoses as high up as possible. A leaking flanged or C-clip axle seal could be just a bad seal, or it could mean an axle bearing or shaft is shot too.
Overly bent axlehousings will typically need to be replaced, especially those with cast center sections. Once the tubes have stretched the cast housing bores that they are pressed into, the axle assembly becomes significantly weaker. Welding the tubes to the cast centersection and re-welding leaky and cracked plug welds should only be considered a temporary repair.
Any brake fluid leaks should be repaired immediately. Check that the brake lines are not kinked, chaffed, or rubbing on the tires or suspension components. Those that frequent the mud should remove the brake calipers, pads, and drums for regular flushing. If you see gouges in the rotors, you likely have a rock or two embedded in the brake pads that will need to be pried out. Oil-soaked brake linings should be replaced and the oil leak should be repaired to ensure the best braking performance possible. It’s a good idea to flush the brake fluid at least once a year or so for those that live in damp environments. Brake fluid absorbs water, which causes corrosion in the system. You can significantly improve brake performance by switching to EBC (ebcbrakes.com) Orangestuff or Yellowstuff brake pads.
Suspension and Frame
Now is a good time to address any nagging problems that pop up on the trail, such as broken shock mounts or coil springs unseating out of their pockets. Look for bent or broken leaf springs and other battered suspension components. Four-link brackets are notorious for pulling themselves free from the frame on Jeeps with aftermarket suspensions and larger tires. Inspect the welds around these brackets for cracks and rust. Many Jeep CJs and some FSJs are notorious for cracked frames around the steering box area. Inspect it carefully. Repair and reinforce anything that’s damaged.
Wallowed out boltholes and loose hardware can cause all sorts of handling problems. Pay particular attention to track bars, track bar hardware, and the related brackets. It’s a good idea to mark all suspension hardware with a paint pen to easily identify if it’s loosened later on. Replace broken zerk fittings and regularly grease all chassis and suspension fittings. You can unclog stopped-up greaseable bolts and fittings with an IPA Grease Joint Rejuvenator (ipatools.com).
Follow the wiring and fuel lines along the framerails to make sure they are routed up and out of harm’s way. This is the perfect time to check the entire frame for cracks. They will most often form near crossmembers or other mounting points.
Start by inspecting the tie rod and draglink for bends and kinks. A bent tie rod or draglink that is supposed to be straight usually won’t last long on the trail, which just happens to be the last place you want to replace either. With the engine off and the steering column unlocked, have a buddy steer the wheel from right to left about 1⁄4-turn each way, while you look for worn and loose components. Carefully look over any and all steering hardware, tie-rod ends, rod ends, steering arms, ball joints, steering-box mounts, the pitman arm, and so on. If anything appears to have slop, it will need to be replaced or tightened. A telltale sign of loose hardware is that dirt and grime will be pushed away from the hardware heads. If left loose for too long, you’ll need to repair the resulting wallowed out boltholes. Tapered tie-rod ends and ball joints are less likely to come loose than a rod end or uniball that uses a straight-shank bolt. Use fine-thread locking hardware and thread-locking compound in these important applications. It’s also a good idea to mark the hardware with a paint pen once it’s tightened. Consider adding a Howe (howeperformance.com), PSC motorsports (pscmotorsports.com), or a Redneck Ram (westtexasoffroad.homestead.com) ram-assist steering system to Jeeps with tires that are 37 inches or bigger, especially if you frequent the rocks. A properly installed ram-assist will take a lot of stress off of the factory steering box.
Tires and Wheels
If your tires are cracked and dry rotted, they should be replaced. Check the tires for wear and cuts. If less than 1⁄16-inch of tread is left, the tires should be replaced. The truth is, your Jeep’s on- and especially off-road performance will benefit from replacing the tires long before you get to the minimum tread depth. Cuts in the tread and sidewall could mean the tires are rubbing the body metal on your Jeep. Lower the bump stops or remove the offending fender bits to prevent further tire damage.
If at some point you had to put tire plugs in a sidewall, replace the tire. A sidewall repair can easily tear farther or the plugs can be spit out, causing an unexpected flat tire, something you don’t want at speed on the highway. Repairing a sidewall for street use is unsafe and illegal.
Check the lug nuts and torque them properly. New wheels have a tendency to loosen lug nuts, so check them every couple hundred miles for the first 1,000 miles or so. Inspect the wheels for dents, damage, and air leaks. Many wheels can be repaired if they are bent or broken. Deflate the tires before checking the torque on beadlock rings. Damaged bolts or wheels could cause an explosion when torqueing the beadlock rings to spec. Don’t forget to give the valve stems a once over. We’ve found that cheap imported valve stems will dry rot long before a tire and sometimes metal stems get damaged by rocks. Questionable valve stems should be replaced.