What transmission is in a Jeep Cherokee XJ 2000? The 4.0-liter engine pairs with either the AW4 four-speed automatic or the AX-15 five-speed manual. If you own or are looking to buy a 2000 Jeep Cherokee XJ, knowing which transmission you have is key for repairs, upgrades, or even just understanding your rig better. This guide breaks down both options, their specs, common issues, and how to tell them apart quickly.
The 2000 model year was the last for the beloved XJ Cherokee before the 2001 redesign. It came with two main transmission choices, both known for durability. Let’s get straight into what makes each one tick.
What Transmission Is In A Jeep Cherokee Xj 2000
The answer depends on whether you have an automatic or manual transmission. The AW4 automatic is the most common, found in the vast majority of XJs. The AX-15 manual is rarer but highly sought after by off-roaders and purists. Both are built to handle the 4.0-liter inline-six’s torque.
Here is a quick breakdown of the two transmissions:
- AW4 (Automatic): A four-speed overdrive unit built by Aisin-Warner. It is electronically controlled and known for its toughness.
- AX-15 (Manual): A five-speed manual built by Aisin-Warner as well. It is a non-electronic, fully mechanical unit.
Neither transmission is a weak point on the 2000 XJ. The AW4 is often called “bulletproof” by enthusiasts. The AX-15 is equally respected for its reliability.
AW4 Automatic Transmission Details
The AW4 is a four-speed automatic with overdrive. It uses a lock-up torque converter for better highway fuel economy. It is controlled by the engine computer (ECU) and has no separate transmission control module.
Key specs for the AW4 include:
- Gear ratios: 1st (2.80), 2nd (1.53), 3rd (1.00), 4th (0.70), Reverse (2.39)
- Fluid type: Dexron III or equivalent (not ATF+4)
- Fluid capacity: About 8 quarts for a drain and fill
- Weight: Approximately 140 pounds dry
The AW4 is a heavy-duty unit. It was also used in some Toyota Supra and Lexus models, which speaks to its strength. It handles the 4.0-liter’s 190 horsepower and 225 lb-ft of torque without breaking a sweat.
Common AW4 Issues
While reliable, the AW4 does have a few weak points. The most common is the transmission cooler lines rusting and leaking. Another is the shift solenoid pack failing, which can cause erratic shifting or no shifting at all.
Here are signs your AW4 might need attention:
- Slipping between gears, especially when hot
- Delayed engagement into Drive or Reverse
- Burning smell from the fluid
- Check Engine Light with transmission-related codes
Regular fluid changes every 30,000 miles can prevent most issues. Use only Dexron III or a high-quality synthetic equivalent. Never use ATF+4 in an AW4.
AX-15 Manual Transmission Details
The AX-15 is a five-speed manual with a single overdrive gear. It is a non-synchronized reverse gear, meaning you must stop completely before shifting into reverse. It is a tough, simple unit that can last hundreds of thousands of miles.
Key specs for the AX-15 include:
- Gear ratios: 1st (3.83), 2nd (2.33), 3rd (1.44), 4th (1.00), 5th (0.79), Reverse (4.22)
- Fluid type: 10W-30 motor oil or MT-90 synthetic
- Fluid capacity: About 3.5 quarts
- Weight: Approximately 75 pounds dry
The AX-15 is lighter than the AW4. It also has a different bellhousing pattern. The 2000 XJ uses an external slave cylinder, which is easier to replace than the internal ones on earlier models.
Common AX-15 Issues
The AX-15 is very reliable, but it has a few known problems. The most common is the shift fork pad wearing out, causing difficulty shifting into gear. Another is the rear output shaft seal leaking.
Here are signs your AX-15 might need attention:
- Grinding when shifting into 2nd or 3rd gear
- Difficulty getting into reverse
- Whining noise in neutral or while driving
- Fluid leaking from the rear seal
Change the fluid every 30,000 miles. Use 10W-30 motor oil or a dedicated manual transmission fluid like Red Line MT-90. Do not use gear oil, as it is too thick.
How To Identify Which Transmission You Have
If you are not sure which transmission is in your 2000 XJ, there are a few easy ways to check. First, look at the shifter. If it has a manual stick with five forward gears, it is the AX-15. If it is an automatic with P-R-N-D-2-1, it is the AW4.
But there is more to it than that. Here is a step-by-step guide to confirm:
- Open the hood and look at the transmission bellhousing. The AW4 has a rectangular shape with a large electrical connector on the driver’s side. The AX-15 has a rounder shape with no electrical connectors.
- Check the transmission pan. The AW4 has a square-ish pan with 14 bolts. The AX-15 has no pan, just a drain plug on the bottom.
- Look at the driver’s side of the transmission. The AW4 has a large shift solenoid pack with wires. The AX-15 has a mechanical shift lever.
- Check the VIN plate or build sheet. The VIN does not directly tell you the transmission, but the build sheet does. You can get a build sheet from Jeep with the VIN.
Another quick trick: the AW4 has a dipstick on the passenger side of the engine bay. The AX-15 does not have a dipstick. If you see a dipstick, it is an automatic.
Transmission Cooler Lines And Maintenance
Both transmissions need proper cooling. The AW4 uses transmission cooler lines that run to the radiator. These lines are prone to rust and failure. If they burst, you lose all transmission fluid and can destroy the transmission.
For the AW4, replace the cooler lines with stainless steel or copper lines. This is a common upgrade. For the AX-15, there are no cooler lines, but the transmission still gets hot. Use a transmission cooler if you tow or off-road heavily.
Here is a maintenance checklist for both:
- Check fluid level monthly (AW4 only)
- Change fluid every 30,000 miles
- Inspect cooler lines for rust (AW4 only)
- Check for leaks at the rear seal
- Listen for unusual noises
Neglecting maintenance is the number one cause of failure. A well-maintained AW4 or AX-15 can easily last 200,000 miles or more.
Swapping Transmissions In The 2000 XJ
Some owners swap transmissions. A common swap is putting an AW4 into a manual XJ, or an AX-15 into an automatic XJ. Both swaps are possible but require different parts.
For an AW4 swap, you need:
- AW4 transmission and torque converter
- Transmission cooler lines
- Shift cable and bracket
- ECU from an automatic XJ
- Flexplate and starter
For an AX-15 swap, you need:
- AX-15 transmission and bellhousing
- Clutch kit, flywheel, and pressure plate
- Clutch master and slave cylinder
- Pedal assembly from a manual XJ
- ECU from a manual XJ
Both swaps are labor-intensive but doable for a skilled DIYer. The AX-15 swap is more common because the manual is rarer and more desirable for off-roading.
Performance Upgrades For Each Transmission
If you want to improve performance, there are upgrades for both. For the AW4, you can install a shift kit to firm up shifts. This reduces slippage and heat. You can also add a larger transmission cooler for towing.
For the AX-15, upgrades include a short-throw shifter for quicker shifts. A heavier flywheel can help with clutch engagement. A clutch upgrade is recommended if you add power to the engine.
Here are popular upgrades:
- AW4 shift kit (TransGo or similar)
- AW4 external transmission cooler
- AX-15 short-throw shifter (B&M or similar)
- AX-15 heavy-duty clutch (Luk or Centerforce)
- Both: synthetic fluids for better heat resistance
These upgrades can extend the life of your transmission and improve driving experience. They are not necessary for stock vehicles but are worth it for off-road or performance use.
Cost Of Replacement Or Repair
If your transmission fails, replacement costs vary. A used AW4 can be found for $200 to $500. A rebuilt unit costs $1,000 to $1,500. A new one is rare but can cost over $2,000.
For the AX-15, used units are $300 to $600. Rebuilt ones are $1,200 to $1,800. New units are hard to find but can be $2,500 or more.
Labor costs for a swap are typically $500 to $1,000 at a shop. DIY saves money but requires tools and time. A rebuild is cheaper than a swap if the transmission is still good.
Here is a cost breakdown:
- AW4 used: $200-$500
- AW4 rebuilt: $1,000-$1,500
- AX-15 used: $300-$600
- AX-15 rebuilt: $1,200-$1,800
- Labor for swap: $500-$1,000
Always check the condition of the transmission before buying used. Look for leaks, test drive if possible, and ask for maintenance history.
Frequently Asked Questions
Q: What transmission is in a 2000 Jeep Cherokee XJ with the 4.0 engine?
A: It is either the AW4 automatic or the AX-15 manual. The AW4 is more common.
Q: Is the AW4 transmission reliable?
A: Yes, the AW4 is very reliable. With regular fluid changes, it can last over 200,000 miles.
Q: Can I swap an AX-15 into an automatic 2000 XJ?
A: Yes, but it requires a clutch pedal, master cylinder, and other parts. It is a common swap.
Q: What fluid does the AW4 use?
A: Use Dexron III or a synthetic equivalent. Do not use ATF+4.
Q: How do I know if my 2000 XJ has the AW4 or AX-15?
A: Check the shifter. If it is a manual with five gears, it is the AX-15. If it is an automatic, it is the AW4. Also look for a dipstick.
Understanding what transmission is in a Jeep Cherokee XJ 2000 helps you maintain it properly. Both the AW4 and AX-15 are excellent units. Keep up with fluid changes and address leaks quickly. Your XJ will reward you with years of reliable service.
If you are planning to buy a 2000 XJ, test drive both if possible. The automatic is easier in traffic. The manual is more engaging off-road. Either way, you are getting a solid drivetrain.
Remember to check the transmission fluid condition before purchase. Dark or burnt fluid is a red flag. A healthy transmission shifts smoothly without slipping. With proper care, your 2000 Jeep Cherokee XJ will be a dependable vehicle for years to come.