Jeep Xj 4.0 Auto: Your Ultimate Transmission Guide

If you own a Jeep Cherokee XJ with a 4.0-liter inline-six engine, you're familiar with its robust performance and reliability. However, understanding the automatic transmission that comes with this engine, known as the AW4 or in later models the 42RLE, is crucial for maintaining its longevity and performance. This guide will walk you through everything you need to know about the Jeep XJ 4.0 Auto, from basic maintenance to advanced troubleshooting.

Understanding the AW4 and 42RLE Transmissions

The Jeep Cherokee XJ was fitted with two primary types of automatic transmissions:

• AW4: Used in models from 1987 to 2001, this 4-speed automatic was known for its durability and simplicity.
• 42RLE: Introduced in 2002 models onwards, it's an electronically controlled transmission offering better fuel efficiency and gear ratios.

Differences:

<p class="pro-note">💡 Pro Tip: Always refer to your vehicle's manual to confirm which transmission you have, as modifications and upgrades can affect this.</p>

Maintenance Basics for Your Transmission

Fluid Checks

Regular transmission fluid checks are imperative for Jeep XJ owners. Here's how:

1. Transmission Fluid Inspection:

   • Park on a flat surface, engine idling in park, and allow the transmission to warm up.
   • With the engine still running, locate the dipstick, typically next to the engine, and check the fluid level. The fluid should be between the “Full” and “Add” marks.

2. Fluid Replacement:

   • AW4: Replace every 30,000 to 50,000 miles or 2-3 years.
   • 42RLE: Follow the schedule, typically 60,000 miles or 4 years.

   <p class="pro-note">💡 Pro Tip: When changing fluid, consider using a transmission cooler for extra longevity, especially in hot climates or towing scenarios.</p>

Filter and Pan Cleaning

Clean or replace the filter every fluid change:

• Remove the pan, clean any gasket material from the mating surface.
• Replace or clean the filter if it's reusable.
• Install a new pan gasket to ensure a proper seal.

Routine Checkpoints

• Pan Gasket: Inspect for leaks. Replace if torn or broken.
• Shift Linkage: Ensure the shift mechanism is moving freely and engaging properly.

Advanced Tips for Optimal Performance

Tuning and Upgrade Options

For those looking to enhance their Jeep XJ's transmission performance:

• Shift Kit: A popular aftermarket upgrade to improve shift feel and durability.
• Torque Converter: Upgrading to a higher stall speed can improve acceleration.

💡 Pro Tip: Always check the compatibility of any aftermarket parts with your Jeep model year and transmission type.

Handling Issues and Troubleshooting

Common Transmission Issues

• Rough Shifting or Delays: Often related to fluid, filter issues, or the valve body.
• Slips or Fails to Engage: This could be due to internal transmission wear, fluid level, or electronic sensor problems.
• Leaking: Check for damaged seals, pan gasket, or fluid lines.

Troubleshooting Steps

1. Check Fluid: Ensure it's at the right level and condition.
2. Inspect for Leaks: Look for puddles, stains, or drips.
3. Listen for Abnormal Noises: Rattles or whines might indicate gear wear or fluid issues.
4. Examine the Solenoid: Particularly with the 42RLE, solenoids can fail or malfunction.

💡 Pro Tip: Always perform basic troubleshooting like checking fluid before considering significant repairs or replacements.

FAQs for Jeep XJ 4.0 Auto Transmission

<div class="faq-section"> <div class="faq-container"> <div class="faq-item"> <div class="faq-question"> <h3>How often should I change my transmission fluid?</h3> <span class="faq-toggle">+</span> </div> <div class="faq-answer"> <p>Change the transmission fluid in an AW4 every 30,000 to 50,000 miles, and for 42RLE, typically every 60,000 miles or as per your vehicle's maintenance schedule.</p> </div> </div> <div class="faq-item"> <div class="faq-question"> <h3>What type of fluid should I use in my Jeep XJ's transmission?</h3> <span class="faq-toggle">+</span> </div> <div class="faq-answer"> <p>AW4 uses Dexron III or ATF+3; 42RLE uses ATF+4 or equivalent, consult your owner's manual for precise fluid specifications.</p> </div> </div> <div class="faq-item"> <div class="faq-question"> <h3>Can I install a transmission cooler on my Jeep XJ?</h3> <span class="faq-toggle">+</span> </div> <div class="faq-answer"> <p>Yes, installing a transmission cooler can extend the life of your transmission, particularly in high-stress scenarios like towing or extreme temperatures.</p> </div> </div> <div class="faq-item"> <div class="faq-question"> <h3>Why does my Jeep XJ shift roughly, especially when cold?</h3> <span class="faq-toggle">+</span> </div> <div class="faq-answer"> <p>This might be normal due to fluid viscosity changes with temperature. However, persistent issues could indicate low fluid levels, dirty fluid, or worn internal components.</p> </div> </div> <div class="faq-item"> <div class="faq-question"> <h3>What are the signs that my transmission might need attention?</h3> <span class="faq-toggle">+</span> </div> <div class="faq-answer"> <p>Watch for delayed engagement when shifting into drive or reverse, slipping gears, harsh or erratic shifts, fluid leaks, unusual noises like grinding or whining, or a check engine light with transmission-related codes.</p> </div> </div> </div> </div>

Wrapping Up and Moving Forward

Taking care of your Jeep Cherokee XJ's transmission is not just about longevity; it's about enhancing your driving experience. From routine maintenance to understanding how to spot and address issues, this guide has covered the essentials of keeping your 4.0 Auto transmission in top shape.

Don't forget to explore related articles and tutorials that delve into specific modifications, advanced troubleshooting, or even how to diagnose electronic issues with the 42RLE transmission. Engaging with a community of Jeep XJ enthusiasts can also provide invaluable insights and real-world experience.

<p class="pro-note">💡 Pro Tip: Regular maintenance and early detection of issues are key to avoiding costly transmission repairs. Always listen to your Jeep's cues and respond promptly.</p>