If you own a 1999 Jeep Cherokee, you know it is a legend of off-road capability and rugged reliability. But even legends need maintenance, and few jobs are as intimidating as dealing with the transmission. Specifically, the torque converter seal—a small but critical component that prevents fluid leaks and ensures your transmission operates under proper pressure. When this seal fails, it can lead to slipping gears, overheating, and eventually, a complete transmission failure. Understanding how to install a new torque converter seal using a proper diagram is not just a repair; it is an investment in the longevity of your vehicle.
This comprehensive guide will walk you through the entire process of installing a transmission in your 1999 Jeep Cherokee, with a laser focus on the torque converter seal. You will learn the anatomy of the transmission system, the tools required, the step-by-step installation procedure, and common pitfalls to avoid. Whether you are a seasoned DIY mechanic or a first-time Jeep owner, this article provides the authoritative, practical knowledge you need to get the job done right. By the end, you will have the confidence to tackle this repair and keep your Cherokee on the road for years to come.
Understanding the 1999 Jeep Cherokee Transmission and Torque Converter Seal
The 1999 Jeep Cherokee typically came equipped with either the Aisin-Warner AW-4 four-speed automatic transmission or the AX-15 five-speed manual transmission. For the purposes of this guide, we will focus on the AW-4, which is the most common and requires the most attention regarding the torque converter seal. The torque converter is a fluid coupling that connects the engine to the transmission, and its seal is a rubber or silicone ring that prevents transmission fluid from leaking out where the converter meets the transmission housing. A failing seal often manifests as a puddle of red fluid under the bellhousing area, a burning smell, or erratic shifting.
The torque converter seal is located deep within the bellhousing, pressed into the pump housing. It is a wear item that can harden, crack, or become dislodged over time, especially if the transmission has been overheated or if the fluid has not been changed regularly. When replacing the transmission, or even just the torque converter, it is standard practice to replace this seal as a preventative measure. Ignoring a worn seal can lead to air being drawn into the transmission pump, causing cavitation, loss of hydraulic pressure, and eventual destruction of the transmission internals. The cost of a new seal is under $20, while a transmission rebuild can exceed $2,000.
To properly install a new torque converter seal, you must first understand the orientation of the transmission and the torque converter. The converter has a pilot hub that slides into the seal, and the seal must be perfectly centered to avoid leaks. Using a factory service manual diagram or a high-quality aftermarket diagram is essential because it shows the exact depth the seal must be seated and the direction of the sealing lip. Many DIY failures occur because the seal is installed backwards or at the wrong depth, leading to immediate failure upon startup.
Essential Tools and Safety Precautions for the Job
Before you begin, gathering the right tools will save you hours of frustration. For this job, you will need a floor jack and jack stands, a transmission jack (or a sturdy helper), a socket set including metric and standard sizes, a torque wrench, a seal puller or a flathead screwdriver, a seal driver kit (or a large socket that matches the seal diameter), a drain pan, and new transmission fluid. You will also need a new torque converter seal specific to the 1999 Jeep Cherokee AW-4 transmission, which you can purchase from any auto parts store or online retailer. Do not use a universal seal; it must match the exact dimensions of your pump housing.
Safety is paramount when working under a vehicle. Always chock the rear wheels, engage the parking brake, and use jack stands rated for at least three tons. Never rely solely on a hydraulic jack. The transmission assembly is heavy—approximately 100 to 120 pounds—so ensure your transmission jack is properly secured. Wear safety glasses to protect your eyes from falling debris and fluid, and use mechanic gloves to avoid cuts from sharp edges on the bellhousing. Work in a well-vent area, as transmission fluid fumes can be irritating.
A critical safety step is to disconnect the negative battery terminal before starting any work. This prevents accidental short circuits and ensures the starter cannot engage while you are working near the flywheel. Also, be aware that the torque converter is filled with fluid and can be heavy. When you remove the transmission, the converter may slide forward and fall out if not properly secured. Always have a drain pan ready to catch any residual fluid that spills from the converter or the transmission tail shaft. Preparation is the difference between a smooth job and a messy, dangerous one.
Step-by-Step Removal of the Transmission and Torque Converter
Begin by raising the vehicle on jack stands and placing a drain pan under the transmission pan. Remove the transmission pan bolts and carefully lower the pan to drain the fluid. Be prepared for a significant amount of fluid—up to 4 quarts. Once drained, remove the filter and clean the pan and magnet thoroughly. Next, disconnect the transmission cooler lines from the radiator or auxiliary cooler. Use a line wrench to avoid rounding the fittings. Plug the lines and the transmission ports to prevent debris from entering.
With the fluid drained, you can now remove the driveshaft. For a 1999 Cherokee, you will have a front and rear driveshaft. Mark the orientation of the driveshafts to the differential flanges before unbolting them. Slide the driveshafts out of the transmission tail housing and set them aside. Next, disconnect the shift linkage, the speed sensor connector, and the transmission range sensor connector. Remove the starter motor (two bolts) and set it aside. Then, support the transmission with a transmission jack and remove the crossmember that supports the rear of the transmission.
Now you are ready to separate the transmission from the engine. Remove the bellhousing bolts that connect the transmission to the engine block. There are typically six to eight bolts, with the top ones being the most difficult to reach. You may need a long extension and a swivel socket. Once all bolts are removed, carefully pry the transmission away from the engine using a flathead screwdriver between the bellhousing and the engine block. As you pull the transmission back, the torque converter will slide out of the flexplate. Secure the converter to the transmission with a zip tie or a strap to prevent it from falling out. Lower the transmission and move it to a clean work area.
Installing the New Torque Converter: The Critical Step
With the transmission on a bench, locate the torque converter seal at the front of the transmission pump housing. Use a seal puller or a flathead screwdriver to carefully pry the old seal out. Be extremely careful not to scratch or gouge the aluminum pump housing, as any damage will cause a leak. Clean the seal bore with a lint-free rag and brake cleaner to remove any old sealant, dirt, or debris. Inspect the bore for any burrs or nicks; if present, use fine-grit sandpaper to smooth them out.
Now, take your new torque converter seal and apply a thin layer of transmission fluid to the outer edge and the sealing lip. This lubricant will prevent the seal from tearing during installation. Using a seal driver kit or a large socket that matches the outer diameter of the seal, gently tap the seal into the bore. The seal must be driven in straight and to the correct depth. Refer to your diagram: the seal should be flush with the face of the pump housing, not recessed or protruding. A common mistake is driving the seal too deep, which can block fluid passages and cause pump failure. Tap it in evenly until it seats fully.
Before reinstalling the torque converter, inspect the converter hub for wear or grooves. If the hub is scored, the new seal will fail quickly. In that case, you need a new torque converter. Apply a thin coat of transmission fluid to the converter hub and carefully slide the converter into the transmission. You will feel it engage the pump splines and then drop into place. You should hear and feel three distinct clicks as the converter fully seats. Measure the distance from the converter mounting pads to the bellhousing face; it should be approximately 1 inch. If the converter is not fully seated, it will destroy the pump when you bolt the transmission to the engine.
Reassembly, Fluid Fill, and Final Checks
With the torque converter fully seated and secured with a zip tie, lift the transmission back into position. Align the converter with the flexplate and slide the transmission forward. You may need to rotate the converter slightly to align the splines. Once the bellhousing is flush with the engine block, install the bellhousing bolts and torque them to factory specifications (typically 35-45 ft-lbs). Remove the zip tie from the converter, then install the flexplate-to-converter bolts. Torque these bolts in a star pattern to 40-45 ft-lbs.
Reinstall the starter motor, the crossmember, and the driveshafts. Reconnect the shift linkage, speed sensor, and transmission cooler lines. Lower the vehicle and fill the transmission with the correct fluid—Dexron III or Mercon V for the AW-4. Start the engine and let it idle for a minute, then check the fluid level with the transmission in Park. Add fluid as needed, cycling through the gears to purge air from the system. Check for leaks around the bellhousing and cooler lines.
Finally, take the Jeep for a test drive. Drive gently at first, then through all gears, including reverse. Listen for unusual noises and watch for any fluid drips. After the test drive, recheck the fluid level and top off if necessary. The torque converter seal should now be leak-free, and your transmission should shift smoothly. This repair not only saves you hundreds of dollars in labor costs but also gives you the satisfaction of knowing your Cherokee is running at its best.
Frequently Asked Questions
What are the symptoms of a bad torque converter seal on a 1999 Jeep Cherokee?
The most common symptom is a transmission fluid leak at the front of the transmission, near the bellhousing. You may notice red fluid dripping onto the ground, a burning smell from fluid hitting the exhaust, or low fluid levels causing slipping or harsh shifting. In severe cases, the transmission may overheat or fail to engage gears.
Can I replace the torque converter seal without removing the transmission?
No, the torque converter seal is located inside the bellhousing, between the transmission and the engine. To access it, you must remove transmission from the vehicle. This is a major job, but it is the only way to properly replace the seal without damaging the new one.
How long does it take to replace a torque converter seal on a 1999 Jeep Cherokee?
For an experienced DIY mechanic, the job typically takes 6 to 8 hours. This includes draining fluid, removing the transmission, replacing the seal, and reinstalling everything. For a first-timer, plan for a full weekend. Having a helper and the right tools can significantly reduce the time.
Do I need to replace the torque converter when replacing the seal?
Not always, but it is highly recommended if the converter hub is worn or scored. Inspect the hub for grooves or pitting. If the hub is damaged, the new seal will fail quickly. If the converter is in good condition and the vehicle has reasonable mileage, you can reuse it. However, many mechanics replace the converter as a preventative measure.
What type of transmission fluid should I use for the 1999 Jeep Cherokee AW-4?
The AW-4 transmission requires Dexron III or Mercon V automatic transmission fluid. Do not use Dexron VI or any synthetic blend unless it explicitly states compatibility with Dexron III. Using the wrong fluid can cause shifting issues and damage the transmission over time.
Conclusion
Replacing the torque converter seal on your 1999 Jeep Cherokee is a challenging but rewarding task that directly impacts the health of your transmission. By following the step-by-step guide outlined here, you have learned how to safely remove the transmission, install the new seal with precision, and reassemble everything correctly. The key to success lies in preparation—using the right tools, referencing a proper diagram, and taking your time to ensure the seal is seated perfectly. This repair not only stops leaks but also restores the hydraulic integrity of your transmission, preventing costly future failures.
Now that you have this knowledge, you can approach the job with confidence. Whether you are restoring a classic Cherokee or maintaining a daily driver, the skills you have gained here are transferable to many other automotive repairs. Remember to always prioritize safety, double-check your work, and consult a factory service manual for torque specifications. Your 1999 Jeep Cherokee is a durable machine, and with proper care, it will continue to serve you reliably for many more years. Get your tools ready, and take the first step toward a leak-free transmission today.
“Cars aren’t just machines. They’re freedom, memory, and a little bit of grease under your fingernails.”
I’m Theodore Roosevelt—though my friends just call me “Ted” (and no, I’m not related to the president, though I do share his love for adventure). I grew up in Detroit in the 1970s, back when the city was still the heart of the American auto industry. My first love was a rusted-out 1967 Mustang my father and I rebuilt in our garage when I was fifteen. That project taught me that cars have souls. After spending twenty years as a mechanic and another ten writing for magazines, I started this blog to help everyday drivers and weekend wrenchers feel confident under the hood. Whether you’re restoring a classic or just trying to keep your daily driver alive for one more winter, I’m here to help you get there.
