The infamous Pentastar tick (often throwing P0300, P0302, P0304, or P0306 codes) is a mechanical failure in the valvetrain. Specifically, the needle bearings inside the rocker arms (cam followers) collapse. When these bearings fail, the roller stops spinning and begins to drag directly across the camshaft lobe.

If left unchecked, it will score and destroy the camshaft, turning a $200 rocker arm job into a $1,500+ camshaft replacement. Early 2012-2013 models also suffered from bad exhaust valve guides/seats on the driver’s side head, which led to Jeep issuing an extended warranty (10 years/150k miles) for the left cylinder head. If you hear a loud, sewing-machine-like ticking from the top of the engine during cold starts, pull the valve covers immediately and inspect the rocker arms.

You have a cracked Oil Filter Housing/Cooler assembly. Chrysler inexplicably made this critical engine component out of plastic. It sits directly in the “V” or valley of the engine block beneath the lower intake manifold.

Why it happens: The #1 cause is overtightening the oil filter cap during an oil change. The cap requires exactly 18 ft-lbs (25 N·m) of torque. Anything more flexes and cracks the plastic housing below it. The oil then pools in the valley and drips down the back of the engine/bellhousing, often being misdiagnosed as a rear main seal leak.

Yes, and mixing them up will destroy your engine.

• 2012-2013 JKs: Use an oil filter with a prominent plastic “nipple” on the bottom (Mopar Part # MO-744).
• 2014-2018 JKs: Use a redesigned, flat-bottom filter (Mopar Part # MO-349).

Mixing Jeep coolants is one of the most fatal mistakes an owner can make.
2007-2012 JKs require 5-Year HOAT (Hybrid Organic Additive Technology), which is usually dyed Orange.
2013-2018 JKs require 10-Year OAT (Organic Additive Technology), which is usually dyed Purple (though it can look pinkish in certain lights).

If you mix HOAT and OAT (or add cheap “Universal Green” coolant from the auto parts store), a chemical reaction occurs that precipitates the silicates. It turns your coolant into a thick, corrosive gel/sludge. This sludge will instantly clog the micro-channels in your heater core (killing your cabin heat) and block your radiator. Fixing it requires a full chemical back-flush and often replacing both the radiator and heater core.

Most mechanics won’t tell you this: the factory track bar and lower control arm brackets on the JK have 9/16″ holes, but from the factory, Jeep used fully threaded 14mm bolts. Because 14mm is slightly smaller than 9/16″, and because the bolts are fully threaded (meaning the sharp threads act like a file against the bracket), the bolts eventually chew out and “wallow” the bracket holes.

Once the hole is wallowed out, the track bar shifts back and forth, inducing violent Death Wobble. The permanent fix is to replace the factory 14mm threaded bolts with Grade 8, 9/16″ fine-thread shouldered bolts (the smooth shoulder prevents grinding the bracket). Companies like Synergy Manufacturing sell complete 9/16″ hardware upgrade kits specifically for this.

You have ruined your factory Caster angle. Caster is the angle of your steering axis (think of the slanted front forks on a chopper motorcycle). A stock JK has about 4.2° of caster, which gives it straight-line stability.

When you lift a JK, the front axle physically rotates downward, which reduces your caster angle to 2° or 3°. This lack of caster makes the steering wheel feel incredibly light, vague, and requires you to constantly correct the wheel to keep the Jeep driving straight.

If you own a 2-Door JK, your rear driveshaft is significantly shorter than a 4-Door Unlimited’s. When you lift a 2-Door past 2.5 inches, the angle between the transfer case and the rear axle becomes extremely steep.

This steep angle binds the factory Rzeppa CV joint at the transfer case output. The rubber boot will eventually tear, slinging a ring of grease onto the underside of your tub, followed shortly by complete driveshaft failure.
The Solution: For a 2-Door lifted over 2.5″, budget for an aftermarket Double-Cardan rear driveshaft (like Adams or Tom Wood’s). You will also absolutely need Adjustable Rear Upper Control Arms to point your rear axle pinion directly up at the transfer case to prevent driveline vibrations.

Forget paying $200+ for an AEV ProCal. The OBD JScan app on your phone paired with a Bluetooth OBD2 reader (like the vLinker MC+) is the most powerful tool for a JK owner.

Step-by-step to calibrate tires:
1. Plug in the OBD2 adapter and turn the ignition to “ON” (engine off).
2. Open JScan, select your JK model, and connect to the adapter.
3. Go to Modules -> TIPM (Totally Integrated Power Module) -> Tire Size.
4. Enter the actual measured height of your tire. (Note: A “35-inch” tire usually measures around 33.75 to 34.25 inches when mounted and under the weight of the Jeep. Measure from the ground to the top of the tire tread).
5. Hit “Write”. Turn the ignition off, then start the Jeep. Your speedometer and automatic transmission shift points are now perfectly recalibrated.

It’s not possessed; your TIPM (Totally Integrated Power Module) has failed. The TIPM is the black fuse box under the hood, but it’s not just a fuse box—it’s a multi-layered circuit board computer that controls nearly every electrical function in the JK.

The most common failure point is the internal Fuel Pump Relay. When this tiny relay burns out, the Jeep will crank endlessly but won’t start, or it will suddenly stall on the highway. Bizarre electrical gremlins (doors locking/unlocking, wipers going off) are classic TIPM death rattles.

The JK uses a Pulse Width Modulation (PWM) system for the headlights. It sends rapid pulses of voltage (instead of a steady 12V stream) to prolong the life of standard halogen bulbs. LEDs react to voltage instantly, so those pulses cause the LED to turn on and off rapidly, creating a terrible flicker.

You have two options:
1. Buy external Anti-Flicker harnesses (CANBUS decoders) and plug them inline.
2. The better way: Use JScan. Go to Modules -> TIPM -> Headlights. Find the setting for “Headlamp Type” or “PWM” and change it from Halogen to LED/Quad. This tells the computer to stop pulsing the voltage, curing the flicker instantly without extra wiring.

Many owners think the Rubicon’s Dana 44 front axle is bulletproof compared to the Sport/Sahara’s Dana 30. This is a dangerous misconception.

What is different: The Dana 44 has a larger, stronger center section (ring and pinion gears), electronic lockers, and thicker 30-spline inner axle shafts.
What is EXACTLY the same: The outer axle tubes, the inner C-knuckles, the ball joints, and the unit bearings (wheel hubs). These are the parts that actually bend or fail under the weight of 35″+ tires. If you plan to wheel a Rubicon hard on 35s or 37s, you still need to weld on C-Gussets and upgrade the ball joints, just like a Dana 30.

If you own an early JK with the 4-speed automatic transmission (42RLE), you might get a “Hot Oil” warning and a chime while driving in deep snow, sand, or off-road.

This happens because the 42RLE lacks an adequate transmission cooler. When you drive off-road in 4-High instead of 4-Low, the torque converter doesn’t lock up. It slips continuously, generating massive amounts of heat that boils the transmission fluid.

Do NOT use standard GL-5 gear oil (like 80W-90)! The NSG370 manual transmission uses yellow brass synchronizers. The sulfur additives in standard GL-5 gear oil will chemically eat and destroy these brass synchros, ruining your transmission.

You must use a fluid that meets Chrysler specification MS-9224. The best options are Mopar Manual Transmission Fluid, Pennzoil Synchromesh, or Royal Purple Synchromax. Change it every 30,000 miles to prevent the infamous “popping out of 1st gear” issue.

Tire size destroys your effective gear ratio, but the engine/transmission combo determines how bad it feels.

• 3.8L Engine (2007-2011): The 4-speed auto is sluggish. If you add 35s, you absolutely must regear to 4.88 or 5.13. Anything less, and the Jeep will constantly hunt for gears on the highway.
• 3.6L Engine (2012-2018): The 5-speed auto (W5A580) is much better. You can survive on factory 4.10 gears (Rubicon). However, to restore snappy factory acceleration and proper overdrive usage, 4.56 is the sweet spot for 35s, and 4.88 for 37s.

This is the most common water leak on the JK. It occurs where the two Freedom Panels meet the windshield header (the A-Pillar).

Common Causes & Fixes:
1. Installation Order: You MUST install the Passenger side panel first, then the Driver side. The driver side has an overlapping lip.
2. Overtightening: Do not overtighten the large black screw-in knobs at the back of the soundbar. Overtightening them acts like a lever, lifting the front lip of the panel off the windshield seal.
3. Mucket Seals: The rubber mucket seals at the top corners of the doors often get pinched. Apply Honda Shin-Etsu grease to plump them back up.

This is galvanic corrosion. Jeep bolted raw aluminum hinges directly to steel doors. Over time, moisture gets trapped between the dissimilar metals, creating a chemical reaction that corrodes the aluminum from the inside out, bubbling the paint.

The Fix: If it’s already bubbling, you must remove the hinges, sand them to bare metal, apply an isolating primer, and repaint. To prevent the hinge pins from seizing inside the door side, punch out the factory metal hinge liners and install aftermarket Delrin (plastic) hinge liners.

Technically yes, but practically no. The factory JK tailgate is rated for approximately 85 lbs. A 35-inch mud-terrain tire mounted on a steel or heavy alloy wheel usually weighs between 95 and 115 lbs.

Over time, the sheer weight and vibration from driving will pop the factory spot welds inside the tailgate skin and bend the factory hinges, causing the tailgate to sag and rattle aggressively. You must install a Heavy-Duty Tailgate Hinge Reinforcement system (like TeraFlex, Morryde, or Rugged Ridge) or a bumper-mounted tire carrier.

First, never use Windex or paper towels on soft top windows. Ammonia destroys the plastic, and paper towels cause micro-scratches.

To restore them, wash them thoroughly with mild car soap and a microfiber mitt. Then, use a specialized plastic restorer like the Novus 3-Step Plastic Polish Kit or RaggTopp plastic window cleaner. Use a dual-action polisher on a very low speed with a foam pad to buff out the scratches and restore crystal-clear visibility.

Your heater core is clogged. This is a very well-documented issue with the 3.6L Pentastar. During manufacturing, casting sand was left inside the engine blocks. As the coolant circulates, this sand collects in the narrowest part of the cooling system: the heater core (which sits behind the dashboard on the driver’s side).

You can try to disconnect the heater core hoses at the firewall and vigorously back-flush it with a garden hose to dislodge the sand. If that fails, the entire dashboard must be removed to replace the heater core.

Your Blower Motor Resistor has burned out. The resistor controls the electrical current to create the slower fan speeds (1, 2, and 3). When it fails, the system bypasses the resistor entirely and only provides full battery voltage (Speed 4).

If the passenger side front floorboard is soaking wet during the summer, your AC Condensation Drain Tube is clogged.

The AC system pulls humidity out of the air, which drains through a rubber tube sticking out of the firewall in the engine bay (passenger side, down low). Mud, spiders, or trail debris often clog this tube. The water backs up into the HVAC box and spills out onto the passenger floor mat. Carefully poke a zip-tie or wire into the rubber tube from the engine bay to unclog it.

Your steering wheel is not perfectly centered. The JK relies heavily on the Steering Angle Sensor located in the clockspring. If you hit a pothole, bent a tie rod, or recently installed a lift kit, the steering wheel might be slightly off-center.

When driving straight, the computer reads the crooked wheel, assumes you are in a slide, and aggressively applies the brakes to individual wheels to “correct” the slide. Loosen the 15mm bolts on the drag link turnbuckle and rotate it until the steering wheel is 100% dead center.

The Rubicon features an electronic sway bar disconnect (Smartbar). The housing for the electric motor is notorious for having terrible factory seals. Water and mud easily bypass the seals, completely frying the circuit board inside.

If the light flashes continuously and the sway bar refuses to connect/disconnect, the motor is dead. A replacement from Mopar is over $1,500. The best solution is to buy a manual conversion dial (like the EVO No-Limits), remove the electric motor, screw in the manual dial, and use JScan to disable the flashing light on the dash.

Yes! The Wrangler JK is one of the most popular vehicles for flat-towing (dinghy towing).

The Procedure:
1. Shift the Transfer Case into NEUTRAL.
2. Shift the Automatic Transmission into PARK (or Manual into gear).
3. Turn the ignition key to the “OFF/UNLOCKED” position. Do NOT remove the key. This prevents the steering wheel from locking, allowing the front wheels to track behind the RV.
Because the transfer case is in neutral, the drivetrain is disconnected from the transmission, meaning no miles will rack up on the odometer.

The golden rule of off-road recovery is to buy a winch rated for 1.5 times the Gross Vehicle Weight (GVW) of your rig.

A stock 4-Door JKU weighs around 4,300 lbs. Once you add steel bumpers, heavy tires, a hardtop, armor, and gear, you can easily exceed 5,300 lbs. Therefore, a 9,000 to 10,000 lb winch is the absolute minimum safe recommendation for a JKU. A 2-Door JK can safely use an 8,000 lb winch.

Yes, highly recommended. The factory JK brakes (single-piston calipers and small rotors) were designed for 29-inch to 32-inch lightweight tires. When you bolt on a heavy 35-inch mud-terrain tire and steel wheel, your stopping distance increases dangerously, and your brakes will fade quickly on downhill mountain passes.

A proper Big Brake Kit (like the TeraFlex or Dynatrac ProGrip) includes larger rotors and dual-piston calipers. If you upgrade the front calipers, you must also upgrade the Master Cylinder and Brake Booster (often sold together as a kit) to push the additional brake fluid required. Without the master cylinder upgrade, your brake pedal will feel extremely mushy.

The 2007-2018 Jeep Wrangler JK uses a 5×5 bolt pattern (also expressed metrically as 5x127mm).

This is not Death Wobble. Shaking that only occurs during braking is a textbook symptom of warped front brake rotors. The heavy weight of oversized tires causes the factory rotors to overheat and warp. Replace them with high-quality slotted (not drilled) rotors and ceramic brake pads.

This is arguably the most common code on the JK. The computer detected a very small vapor leak in the emissions system.

Steps to fix:
1. Gas Cap: Check the rubber O-ring on your gas cap. Clean it, apply a tiny bit of silicone grease, and tighten it until it clicks 3 times. Clear the code.
2. ESIM Switch: The Evaporative System Integrity Monitor (ESIM) is a white plastic switch located on the EVAP canister under the Jeep (near the rear axle). Its internal diaphragm often tears. Replacing the ESIM and its rubber seal usually solves the P0456 code permanently.
3. Vacuum Lines: Check the plastic EVAP lines near the battery tray. They often rub against the battery box and rub a tiny hole through the plastic.

Usually, no. Your engine likely has fine oil pressure, but the Oil Pressure Sensor itself has failed. This is extremely common on the 3.6L Pentastar engine.

Unfortunately, the sensor is located at the absolute bottom of the oil filter housing, buried under both the upper and lower intake manifolds. The labor to get to it is intensive. Because of this, most mechanics recommend replacing the entire Oil Filter/Cooler housing (with the Dorman aluminum upgrade) at the same time, since it includes a new sensor and you’re already paying for the labor to access it.

These codes mean your catalytic converters are no longer cleaning the exhaust gases efficiently.
P0420 = Bank 1 (Passenger side).
P0430 = Bank 2 (Driver side).
Before spending $1,000+ on new catalytic converters, replace the downstream O2 (oxygen) sensors. Often, a lazy O2 sensor will trigger these codes even if the cat is fine. Also, check for exhaust leaks at the Y-pipe joints, as fresh air entering the exhaust can trick the sensors.

Yes, any factory JK hardtop will physically bolt onto any JK of the same wheelbase (2-door to 2-door, JKU to JKU).

However: If your Jeep originally came with only a soft top, it does not have the wiring harness or the plumbing for the rear windshield wiper and the rear defroster. You can still use the hardtop, but those rear features won’t work unless you buy and install the Mopar Hardtop Wiring Kit and have the dealer flash your computer to recognize the new controls.

Jeep offered two types of soft tops.
1. Standard Vinyl: Has a slightly glossy, textured finish. It is easier to clean mud off of, but it is thinner, louder on the highway, and fades to gray over time.
2. Premium Sailcloth (Acrylic): Looks and feels like a thick fabric/canvas (similar to high-end convertible sports cars). It is much deeper black, insulates against heat/cold better, and is noticeably quieter on the highway. If replacing your top, always spend the extra money for the Premium Twill/Sailcloth material.

The JK has a few popular antenna mounting locations, but proper grounding is the real secret.

1. Spare Tire Carrier Mount: The most popular and aesthetically pleasing. However, the tailgate is notoriously badly grounded. If you mount here, you MUST run a dedicated ground strap from the antenna mount directly to the Jeep’s chassis/frame.
2. Cowl / A-Pillar Mount: Mounted near the windshield wipers. Excellent ground connection right out of the box and great reception since it clears the roofline, but the antenna will whip around in your field of vision while driving.

Many people assume the transfer case requires heavy gear oil because it handles 4WD. This is false. The JK’s NV241 (and Rubicon NV241OR) transfer case takes exactly 2 quarts of ATF+4 (Automatic Transmission Fluid). Using gear oil will destroy the internal chain and planetary gears. Change it every 30,000 miles (or immediately if submerged in deep water).

For standard daily driving, use 80W-90 API GL-5 gear oil in both the front and rear axles.

However, if you do heavy towing, extreme off-roading, or own a Rubicon (which has a heavier Dana 44 rear axle), Jeep’s official manual recommends upgrading the rear differential to fully synthetic 75W-140 API GL-5. If your JK has a factory Trac-Lok Limited Slip Differential (LSD) in the rear, ensure your fluid contains a “Friction Modifier” additive, or buy a bottle of Mopar friction modifier and pour it in, otherwise your rear clutches will chatter around corners.

No. The factory JK suspension components (ball joints, tie rod ends, and driveshaft Rzeppa CV joints) are completely “sealed for life” and do not have zerk fittings for grease.

The spark plugs on the 3.6L are rated for 100,000 miles. Changing the passenger side (Bank 1) is very easy and takes 10 minutes.

However, the driver side (Bank 2) is buried entirely underneath the upper intake manifold (plenum). To change the driver side plugs, you must unbolt and remove the entire upper intake manifold. It takes about 1-2 hours for a DIY mechanic. Always buy a new set of upper intake manifold gaskets (rubber O-rings) when doing this job, as the old ones will flatten out and cause a vacuum leak.

An Engine/Oil Pan Skid Plate. While the JK comes from the factory with decent skid plates for the gas tank and transfer case, the engine oil pan and automatic transmission cooler lines are completely exposed.

On the 3.6L Pentastar, the exhaust crossover pipe hangs dangerously low, and sliding over a rock can crush the pipe into the transmission pan. A heavy-duty steel or aluminum engine skid system (like EVO Manufacturing or Metalcloak) is the best insurance policy you can buy for off-roading.

Yes, significantly. Factory JK coil springs (especially on 2-door models without the Max Tow package) are notoriously soft. A heavy steel bumper (100 lbs) plus a winch with steel cable (80 lbs) will easily drop the front of your Jeep by 1 to 1.5 inches, ruining your ground clearance and creating a severe “rake” (nose-down stance).

To fix this, you must either install a stiffer set of aftermarket coil springs, or add a simple 3/4″ to 1″ polyurethane coil spacer on top of the factory front springs.

• Stubby: Barely wider than the grille. Offers maximum clearance for front tires to climb rocks without hitting the bumper. Looks aggressive but offers zero protection for your fenders.
• Mid-Width: Extends to the inner edge of the fenders. A great balance of tire clearance and front-end protection.
• Full-Width: Extends all the way in front of the tires. Heavy, limits off-road approach angles, but provides the best protection against deer strikes or highway accidents.

Do not run a mess of individual wires, inline fuses, and relays directly to your battery terminals. This creates a fire hazard and looks terrible.

Invest in a Relay Switch Pod System (like sPOD or Apollointech). These systems give you a clean row of switches inside the cabin (usually mounted above the rearview mirror) and a single, waterproof relay/fuse box under the hood. You simply connect your light bars directly to the under-hood box, completely eliminating the need to pierce the firewall with multiple wires.

In 2015, Jeep completely redesigned the premium Alpine audio system. Prior to 2015, the subwoofer was a relatively weak unit mounted into the side wall of the cargo area.

The 2015+ Alpine system features a massive, quad-coil subwoofer embedded directly into the cargo floor. This floor-mounted design uses the entire tub of the Jeep as an acoustic enclosure, producing incredibly deep bass. It is also 100% waterproof—if you get caught in the rain with the top off and the sub fills with water, it will still play perfectly (just wipe it out with a towel!).

The JK hardtop is essentially a thin fiberglass shell with zero insulation. To drastically cut down on highway drone, wind noise, and improve your stereo’s sound quality, install a Sound Deadening Headliner Kit.

Kits like Boom Mat or the Mopar Headliners use thick acoustic foam panels that stick directly to the inside roof of the hardtop. As a bonus, they significantly insulate the cabin, keeping it much cooler in the summer sun and warmer in the winter.

The JK’s CANBUS electrical system is hyper-sensitive to voltage drops. Even if your Jeep still starts, a battery that is operating at 11.5V instead of a healthy 12.4V+ will cause the computer modules to miscommunicate. This triggers random ABS lights, traction control warnings, and dashboard chimes. Always load-test your battery if electrical gremlins appear.

Yes. Factory Lead-Acid batteries do not handle the harsh vibrations of off-roading well, and their internal plates can crack. An AGM (Absorbent Glass Mat) battery (like an Odyssey or Optima YellowTop) is completely sealed, spill-proof, handles winch loads much better, and easily survives corrugated dirt roads.

If you run a heavy-duty winch, massive light bars, and an upgraded stereo, the factory wiring from the alternator to the battery is a bottleneck. The “Big 3” upgrade involves running thicker (usually 1/0 AWG) gauge wire for:
1. Alternator positive to battery positive.
2. Battery negative to chassis.
3. Engine block to chassis.
This ensures your electrical system flows maximum current without overheating the wires.

This code is terrifying to see but often simple to fix. The 3.6L Pentastar uses a dual-stage oil pump. It runs at low pressure for idle/cruising, and high pressure for acceleration.

Causes:
1. Wrong Oil Filter: If you put a 2014+ filter in a 2013 housing (or vice versa), the bypass valve stays open, triggering this code instantly.
2. Oil Pump Solenoid: The solenoid on the oil pump itself (located inside the oil pan) has failed. You can replace just the solenoid without buying a whole new pump.
3. Bad Sensor: The oil pressure sensor (P0520) is failing and sending erratic readings to the computer.

You don’t need a mechanic to find loose suspension parts; you just need a friend.

1. Leave the Jeep’s tires on the ground (do not jack it up).
2. Start the engine so the power steering works.
3. Have a friend turn the steering wheel forcefully back and forth from the 10 o’clock to 2 o’clock positions continuously.
4. Crawl under the front of the Jeep with a flashlight. Look closely at the Track Bar bolts, Tie Rod Ends, and Drag Link joints. If you see the joint popping up and down, or a bolt shifting side-to-side inside its bracket, you have found your Death Wobble culprit!

This is a widespread issue on 2007-2010 JKs. The check-valve (roll-over valve) inside the fuel tank filler neck swells due to ethanol in modern gasoline and gets stuck. When the tank gets full, the valve doesn’t close fast enough to trigger the gas pump to click off, resulting in a geyser of fuel spitting out onto your paint. Jeep issued a lifetime warranty extension for the fuel tank on certain early models for this exact issue.

No. Unlike 99% of modern vehicles, the JK hood is only secured by the two exterior rubber latches. Anyone can walk up, unlatch it, and steal your battery or under-hood accessories in seconds.

The factory center console and glove box locks are plastic and can be popped open with a screwdriver in 3 seconds. To truly secure your gear, install heavy-duty, welded steel lockboxes. Companies like Tuffy Security Products make custom-fit steel enclosures that replace the center console insert, slip under the driver’s seat, or completely enclose the rear cargo area (Tailgate Enclosure).

Always do a 5-Tire Rotation. Because you carry a full-size matching spare on the back, you should include it in your rotation every 5,000 miles.

Why?
1. It extends the life of your expensive mud-terrain tires by 20%.
2. If you do a 4-tire rotation and ruin a tire at 30,000 miles, your spare will be brand new (100% tread). If you put that brand-new spare on an axle with a worn tire, the diameter difference will damage your differentials. Rotating all 5 ensures they wear evenly together.

Synthetic Rope is superior in almost every way.
– Safety: If a steel cable snaps under tension, it stores massive kinetic energy and can slice a car (or a person) in half. If synthetic rope snaps, it simply drops dead to the ground.
– Weight: Synthetic rope saves about 25-30 lbs off the nose of your Jeep.
– Handling: Steel frays over time and requires heavy leather gloves to prevent cutting your hands. Synthetic is soft and easy to spool.
Note: Synthetic rope is sensitive to UV degradation and abrasion against sharp rocks, so keep it covered and use a protective sleeve when winching over ledges.

It is a time-honored tradition. When two Jeep Wranglers pass each other on the road, drivers acknowledge each other with a wave. It can be a full hand wave out the window, or just lifting two or four fingers off the steering wheel. If you drive a Wrangler, it is an unwritten rule that you must wave back!