2018 Jeep Wrangler Fluid Type Specs

Quick Reference

Fluid	Type/Spec	Capacity
Engine Oil	SAE 5W-20 / 5W-30 (refer to owner's manual for specific engine) API SP / SN Plus, ACEA A1/B1 or A5/B5, Chrysler MS-6395	6.0 - 6.4 quarts (3.6L Pentastar) / 5.0 quarts (2.0L Hurricane), verify in owner's manual
Engine Coolant	Mopar OAT Antifreeze/Coolant, Pink/Purple, MS-90032	10.0 - 14.0 quarts, verify in owner's manual
Transmission Fluid	Automatic: Mopar ZF 8-Speed ATF, ZF Lifeguard 8 (MS-9602)
Manual: Mopar/Pennzoil Synchromesh Manual Transmission Fluid (MS-9224)	Automatic: 4.8 - 9.0 quarts (Varies based on transmission model and service type - check owner's manual)
Manual: 2.0 - 2.5 quarts (Varies based on transmission model - check owner's manual)
Transfer Case	Mopar ATF+4 Automatic Transmission Fluid (MS-9602)	1.8 - 2.0 quarts, verify in owner's manual
Front Differential	SAE 75W-90, API GL-5, Mopar Axle Lubricant (MS-90030)	1.3 - 1.5 quarts, verify in owner's manual
Rear Differential	SAE 75W-90 (open diff) / SAE 75W-140 with friction modifier (limited slip), API GL-5, Mopar Axle Lubricant (MS-90030)	2.0 - 2.5 quarts, verify in owner's manual
Brake Fluid	Mopar DOT 3/4 Brake Fluid	As needed
Power Steering	Mopar MS-5931 type fluid (refer to owner's manual)	As needed
Washer Fluid	Mopar Windshield Washer Concentrate or equivalent pre-mixed washer fluid	As needed
DEF	N/A (Gasoline engine only)	N/A

Engine Oil

The 2018 Jeep Wrangler offers two distinct engine choices: the 3.6L Pentastar V6 and the new 2.0L Hurricane turbo-four. Each engine has specific oil requirements, so always consult your owner's manual to confirm the exact SAE viscosity grade. Generally, the 3.6L Pentastar V6 typically recommends SAE 5W-20, while the 2.0L Hurricane turbo-four often specifies SAE 5W-30. In both cases, the oil must meet Chrysler material standard MS-6395 and be API certified as SP or SN Plus to protect against low-speed pre-ignition (LSPI) in direct-injected engines. Look for oils also meeting ACEA A1/B1 or A5/B5 for improved fuel economy and engine protection.

Intervals: The recommended oil change interval for the 2018 Jeep Wrangler is typically 10,000 miles or 12 months, whichever comes first, under normal driving conditions. However, if you frequently drive in dusty conditions, tow heavy loads, or engage in extensive stop-and-go city driving, more frequent changes (e.g., every 5,000 miles or 6 months) are advisable. The vehicle's oil life monitoring system will also provide guidance.

Pitfalls: Always ensure the oil you use explicitly states compliance with Chrysler MS-6395. Using oil that does not meet this specification can lead to premature engine wear, reduced fuel efficiency, and potentially void your warranty. Do not mix different oil viscosity grades or synthetic with conventional oils unless specified by the manufacturer.

Engine Coolant

The 2018 Jeep Wrangler utilizes Mopar OAT (Organic Acid Technology) Antifreeze/Coolant, which is typically pink or purple in color. This coolant is formulated to last longer and provide superior corrosion protection compared to older coolant types. It meets Chrysler specification MS-90032.

Intervals: Mopar OAT coolant has a long service life, typically 10 years or 150,000 miles. However, it's good practice to inspect the coolant level and condition periodically. If the coolant appears discolored or murky, it may be time for a flush and refill.

Pitfalls: Never mix OAT coolant with other coolant types, especially HOAT (Hybrid Organic Acid Technology) or traditional green coolants. Mixing different coolant chemistries can result in chemical reactions that form precipitates, clog the cooling system, and lead to severe engine damage. Always use Mopar OAT or an approved equivalent that clearly states compliance with MS-90032.

Transmission Fluid

The 2018 Jeep Wrangler can be equipped with either an automatic or manual transmission, each requiring a specific fluid.

Automatic Transmission (8-speed ZF automatic): This transmission requires Mopar ZF 8-Speed ATF or an equivalent fluid that meets ZF Lifeguard 8 specification. It is crucial to use the correct fluid type, as modern automatic transmissions are highly sensitive to fluid properties. The Chrysler material standard for this fluid is MS-9602, which is also common for ATF+4. However, for the ZF 8-speed, always verify it meets the ZF Lifeguard 8 standard.

Manual Transmission: For manual transmissions, the specified fluid is Mopar/Pennzoil Synchromesh Manual Transmission Fluid, meeting Chrysler specification MS-9224.

Intervals: For both automatic and manual transmissions, fluid service intervals can vary significantly based on driving conditions. In severe duty (towing, off-roading, extensive idling), more frequent changes (e.g., every 30,000-60,000 miles) are recommended. Under normal conditions, automatic transmission fluid might be considered "fill for life" by some manufacturers, but it's always wise to inspect the fluid regularly and consider a change every 60,000 - 100,000 miles. Always refer to your owner's manual for precise intervals.

Pitfalls: Using an incorrect automatic transmission fluid can cause shifting problems, premature wear, and even transmission failure. Never use "universal" ATF products unless they explicitly state compliance with ZF Lifeguard 8 for the automatic or MS-9224 for the manual. For manual transmissions, using gear oil instead of synchromesh fluid can lead to difficult shifting and damage to the synchronizers.

Transfer Case

The 2018 Jeep Wrangler's transfer case typically requires Mopar ATF+4 Automatic Transmission Fluid, which meets Chrysler specification MS-9602. While it's an automatic transmission fluid, it's specifically designed for the demands of the transfer case in many Chrysler/Jeep applications.

Intervals: Transfer case fluid should generally be replaced every 30,000 miles for vehicles subjected to heavy use (off-roading, towing) or every 60,000 miles under normal conditions. Refer to your owner's manual for specific recommendations.

Pitfalls: Do not substitute with other types of automatic transmission fluids unless they explicitly meet the MS-9602 specification.

Front Differential

The front differential typically requires SAE 75W-90, API GL-5 gear lubricant. Mopar specifies their axle lubricant that meets MS-90030.

Intervals: Differential fluid change intervals can vary, but generally, inspection every 20,000-30,000 miles and replacement every 30,000-60,000 miles is a good guideline, especially with off-road use or heavy loads. Always check your owner's manual for precise recommendations.

Pitfalls: Always use an API GL-5 rated gear oil. GL-4 oils are not suitable for differentials requiring GL-5 and can lead to premature wear. Ensure the correct viscosity grade is used.

Rear Differential

The rear differential specification depends on whether your 2018 Jeep Wrangler is equipped with an open differential or a limited-slip differential (LSD).

• Open Differential: Requires SAE 75W-90, API GL-5 gear lubricant. Mopar specifies their axle lubricant that meets MS-90030.
• Limited-Slip Differential (LSD): Requires SAE 75W-140, API GL-5 gear lubricant, and critically, it must contain a friction modifier additive or have one added separately. Without the friction modifier, the LSD clutch packs can chatter and wear prematurely. Mopar also offers an axle lubricant for LSDs that meets MS-90030 and often includes the friction modifier.

Intervals: Similar to the front differential, inspect every 20,000-30,000 miles and replace every 30,000-60,000 miles, particularly with off-road use or towing. Verifying fluid level and condition is even more important for LSDs.

Pitfalls: Incorrect fluid or the absence of a friction modifier in an LSD can lead to chatter, noisy operation, and accelerated wear of the clutch packs. Always verify if your vehicle has an LSD before servicing the rear differential.

Brake Fluid

The 2018 Jeep Wrangler uses Mopar DOT 3 or DOT 4 Brake Fluid. Both are compatible, with DOT 4 offering a slightly higher dry and wet boiling point, which can be beneficial in demanding braking situations or for vehicles engaging in off-road activities where brakes might be worked harder.

Intervals: Brake fluid is hygroscopic, meaning it absorbs moisture over time, which lowers its boiling point and can lead to corrosion in the braking system. It is generally recommended to flush and replace brake fluid every 2-3 years or 30,000 miles, whichever comes first, regardless of mileage. Some manufacturers may extend this, but moisture absorption is a time-dependent process.

Pitfalls: Never use DOT 5 (silicone-based) brake fluid, as it is not compatible with systems designed for DOT 3/4 and can cause severe damage to seals and rubber components. Ensure the cap is kept on the brake fluid reservoir to minimize moisture absorption.

Power Steering Fluid

The 2018 Jeep Wrangler typically uses a specific power steering fluid that meets Chrysler specification MS-5931. Refer to your owner's manual for the exact Mopar fluid or an approved equivalent.

Intervals: Power steering fluid generally has a long service life, but it can degrade over time, especially with heavy use. Inspect the fluid periodically for color and clarity. If it appears dark or has a burnt smell, it might be time for a flush and refill. Some recommend a flush every 50,000-100,000 miles.

Pitfalls: Using an incorrect power steering fluid can lead to pump noise, difficult steering, and premature wear of power steering components. Do not substitute with automatic transmission fluid unless explicitly stated to be compliant with MS-5931.

Washer Fluid

Any commercially available pre-mixed windshield washer fluid is suitable for the 2018 Jeep Wrangler. Mopar also offers a specialized concentrate that can be mixed with water. For colder climates, ensure you use a fluid rated for freezing temperatures.

Intervals: As needed.

Pitfalls: Do not use plain water, especially in freezing temperatures, as it can freeze and damage the washer fluid reservoir and lines.

DEF (Diesel Exhaust Fluid)

The 2018 Jeep Wrangler is available with gasoline engines only in the US market, so DEF is not applicable.

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