In 1990, development of a successor to the YJ began in Chrysler's "Jeep-Truck Engineering Pre-Program" department under Bob Sheaves and TJ program director, Craig Winn. Mules based on the YJ were built from 1990 to 1993, when formal approval was given for the TJ development program at a 0 million budget. From 1991 to 1992 designers worked at the new Chrysler Technical Center, building on various design proposals. In late 1992, Michael Santoro's TJ proposal was chosen by Tom Gale, Lee Iacocca, and executive management. In May 1993, now with engineering and supplier input, Santoro's final Wrangler production design was frozen at 32 months ahead of initial assembly. Verification prototypes using production bodies were built from early 1994 and tested through late 1995. As YJ production ceased in December 1995, the last pre-production TJ examples were assembled, with start of series of production in January 1996. Unveiled on January 2, 1996, at the 1996 Detroit Auto Show as an early 1997 model year introduction (1996 model year skipped), the TJ was an evolutionary update. It later arrived in Jeep showrooms in April 1996, after 6 years of overall investment and 36 month production development phase.Instead of leaf springs, this updated Wrangler featured a modern coil-spring suspension, front and rear, based on that of the Jeep Grand Cherokee, for better ride and handling, and a return to the classic CJ's round headlamps. The engine is the same 4.0 L AMC 242 Straight-6 used in the Cherokee and Grand Cherokee. A 2.5 L AMC 150 Inline-4 engine was available on entry-level models until 2002. The 2.4 L DOHC 4-cylinder engine previously used on the Chrysler PT Cruiser replaced it for 2003.A right hand drive version of the TJ was available for export markets, and was also offered for sale to U.S. rural route postal carriers. The version offered to U.S. postal carriers was only available with an automatic transmission.

In 1998 (MY1999), the fuel tank became standard at 19 U.S. gallons (72 L; 16 imp gal) capacity. There were some changes between the 2002 and 2003 years. From 1996 to 2002, the side door mirrors were black metal framed mirrors; and from 2003 to 2006 they were plastic molded mirrors. The fit of hard and soft tops is slightly different, and the fabric and colors available changed from 2001 to 2003. In 2002 (MY2003), the 3-speed automatic transmission was replaced with a 4-speed automatic with overdrive. The overdrive can be turned off with a dash switch. The radio bezels went from a rectangle in 2002 to a rounded-edged rectangle for 2003. The sound bar inside was changed to sound pods. The interior seats also changed design, going from a rounder model to one with a distinct separation between back and headrest areas. The standard skid plate was also revised for 2003 to make room for the Rubicon's bigger NV241OR transfer case. The change from the 30/32RH to the 42RLE also gained an additional skid plate. This version of the Wrangler is also notable for being the last production vehicle to use AMC-related parts. The AMC Straight-4 engine was retired after the 2002 model year, and both the AMC Straight-6 engine and the door handles (the latter of which first appeared on AMC vehicles in the 1968 model year) were retired along with this generation in 2006. Like the YJ Wrangler, the TJ Wrangler used both the AMC passenger car door handles as well as the larger door handles off the AMC-built Jeep CJ for higher-end models.

 

### Gearbox Oil Change on a Jeep Wrangler TJ

#### Tools Required:
- **Socket Set**:
- **Description**: A set of sockets (usually metric) to remove drain and fill plugs.
- **Usage**: Attach the correct size socket to a ratchet to loosen/remove the bolts.

- **Ratchet**:
- **Description**: A tool that allows you to turn sockets without removing them from the bolt.
- **Usage**: Attach the socket and use the handle to turn clockwise to tighten or counterclockwise to loosen.

- **Torque Wrench**:
- **Description**: A wrench that measures the torque applied to a fastener.
- **Usage**: Ensures that the drain and fill plugs are tightened to the manufacturer’s specifications, preventing leaks.

- **Oil Drain Pan**:
- **Description**: A container to catch the old oil as it drains out.
- **Usage**: Place it under the gearbox to collect the old oil.

- **Funnel**:
- **Description**: A tool to help pour new oil into the fill hole without spilling.
- **Usage**: Insert it into the fill hole of the gearbox to direct the new oil.

- **Shop Rags/Paper Towels**:
- **Description**: For cleaning up spills and wiping tools.
- **Usage**: Keep the work area clean and handle any excess oil.

- **Pliers**:
- **Description**: A tool for gripping and pulling, useful if plugs are stuck.
- **Usage**: Use to grip and twist stuck drain/fill plugs if needed.

#### Steps to Change Gearbox Oil:

- **Preparation**:
- Park the Jeep on a flat surface and engage the parking brake.
- Gather all tools and materials.

- **Drain the Old Oil**:
- Locate the drain plug on the gearbox (usually at the bottom).
- Position the oil drain pan under the drain plug.
- Use the socket and ratchet to remove the drain plug. Let the old oil fully drain into the pan.

- **Inspect the Drain Plug**:
- Check the drain plug for metal shavings or debris. If excessive wear is visible, consider replacing the plug or inspecting for internal damage.

- **Replace the Drain Plug**:
- Clean the drain plug and the area around it.
- Reinstall the drain plug using the torque wrench to tighten it according to manufacturer specifications (check Jeep manual for specific torque settings).

- **Fill with New Oil**:
- Locate the fill plug on the gearbox (usually on the side).
- Remove the fill plug with the socket and ratchet.
- Use the funnel to pour new gearbox oil into the fill hole. Check your Jeep manual for the type and amount of oil required.
- Fill until the oil reaches the fill hole (it should slightly overflow).

- **Replace the Fill Plug**:
- Clean the fill plug and the surrounding area.
- Reinstall the fill plug using the torque wrench to tighten it to specifications.

- **Clean Up**:
- Dispose of the old oil properly at a recycling center.
- Wipe any spills and clean your tools.

#### Replacement Parts:
- **Gear Oil**: Ensure you have the correct type of gear oil (check the owner's manual for specifications).
- **Drain and Fill Plugs**: If damaged or corroded, consider replacing them to ensure a good seal.

### Additional Notes:
- Always consult the Jeep owner’s manual for specific details on oil type, quantity, and torque specifications.
- Regularly changing the gearbox oil maintains performance and prolongs the lifespan of your gearbox.
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- **Tools Needed:**
- **Socket Set**: A basic socket set (typically 3/8 inch drive) with metric sockets (10mm, 12mm, etc.) will be required to remove bolts and nuts. Sockets allow for torque application without stripping fasteners.
- **Ratchet Wrench**: Used with the socket to turn fasteners. The ratchet mechanism allows for continuous turning in one direction without needing to remove the tool from the bolt.
- **Torque Wrench**: To ensure that bolts are tightened to the manufacturer's specifications. This prevents over-tightening which can strip threads or damage components.
- **Pliers**: Useful for gripping or twisting components, especially if they are stuck or difficult to reach.
- **Flathead and Phillips Screwdrivers**: These will help you remove any screws that might be holding components in place.

- **Additional Tools (if needed):**
- **Wrench Set**: A combination wrench set may be required if there are fasteners that cannot be accessed with a socket and ratchet.
- **Hammer or Rubber Mallet**: To gently tap parts that may be stuck or need persuasion to come off.
- **Jack and Jack Stands**: If you need to raise the Jeep for better access, a hydraulic jack and jack stands ensure safety while working underneath the vehicle.

- **Removing the Accelerator Linkage:**
- **Locate the Accelerator Linkage**: It's usually near the throttle body on the engine. The linkage connects the accelerator pedal to the throttle.
- **Disconnect the Battery**: Always disconnect the negative terminal of the battery before working on vehicle components to prevent electrical shorts.
- **Remove Any Covers or Obstructions**: If there are covers over the throttle body or linkage, use the appropriate screwdriver or socket to remove them.
- **Detach the Linkage**: Identify how the linkage is connected (usually a clip or bolt). Use pliers to remove clips or a socket wrench to remove bolts.

- **Inspect the Linkage**:
- Look for any signs of wear, such as cracks or excessive play. If the linkage is damaged, replacement is necessary to ensure proper throttle response and safety.

- **Replacement Part (if needed)**:
- If the linkage is damaged, you may need to replace it with a new accelerator linkage assembly. Check with a local auto parts store or online for the correct part number for a Jeep Wrangler TJ.

- **Installing the New Linkage**:
- **Position the New Linkage**: Place the new linkage in the same position as the old one.
- **Reattach Fasteners**: Use the socket and ratchet to secure any bolts or clips. Make sure they are tightened to the manufacturer's specifications with a torque wrench.
- **Reconnect Any Covers**: If you removed any protective covers, reinstall them using the appropriate tools.
- **Reconnect the Battery**: After everything is secured, reconnect the negative terminal of the battery.

- **Testing**:
- Start the vehicle and press the accelerator pedal to ensure the throttle opens and closes smoothly. Check for any unusual noises or sticking.

- **Final Check**:
- Ensure all tools are removed from the engine compartment and that nothing is left loose or hanging.

By following these steps and using the required tools, you should be able to successfully replace the accelerator linkage on your Jeep Wrangler TJ.
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### Air Intake Tube on a Jeep Wrangler TJ: Detailed Explanation

#### Components of the Air Intake System

1. **Air Filter**:
- **Function**: Cleans the air entering the engine by trapping dirt and debris.
- **Location**: Usually housed in a box near the engine.
- **Analogy**: Think of it as a coffee filter, preventing grounds from entering your drink.

2. **Air Intake Tube**:
- **Function**: Connects the air filter to the throttle body, directing clean air to the engine.
- **Material**: Typically made from plastic or rubber for flexibility.
- **Analogy**: Like a straw that carries your drink from the cup to your mouth.

3. **Throttle Body**:
- **Function**: Controls the amount of air entering the engine based on the position of the accelerator pedal.
- **Location**: Mounted on the intake manifold.
- **Analogy**: Similar to a valve that opens wider when you want more air (or gas) in your drink.

4. **Mass Air Flow (MAF) Sensor**:
- **Function**: Measures the amount of air entering the intake system to help the engine control module (ECM) adjust fuel delivery.
- **Location**: Usually located in the air intake tube.
- **Analogy**: Think of it as a measuring cup that ensures the right amount of ingredients for your recipe.

#### Theory Behind the Repair

The air intake system is crucial because it provides the engine with the correct amount of clean air for combustion. If the air intake tube or any of its components are damaged or clogged, it can lead to:

- **Poor Engine Performance**: Insufficient or dirty air can affect fuel efficiency and power.
- **Increased Emissions**: An improper air-fuel mixture can lead to higher exhaust emissions.
- **Engine Damage**: Contaminants could enter the engine, causing wear or damage over time.

#### How the System Works

1. **Air Flow**: Air enters the air filter through the front grille of the Jeep.
2. **Filtration**: The air filter cleans the air, removing dust and debris.
3. **Transportation**: Clean air travels through the air intake tube to the throttle body.
4. **Control**: The throttle body regulates the flow of air based on driver input (accelerator pedal).
5. **Measurement**: The MAF sensor sends data to the ECM, which adjusts fuel injection accordingly for optimal combustion.

#### Common Issues

1. **Cracks or Leaks**: If the air intake tube has cracks, it can allow unfiltered air into the engine. This is like a leak in your straw, causing you to sip air instead of just juice.

2. **Clogs**: Dust and debris can accumulate, restricting airflow. This is similar to a clogged coffee filter, making it hard to brew a proper cup.

3. **Faulty MAF Sensor**: If the MAF sensor fails, the ECM may not get accurate readings, leading to poor engine performance. Think of it as a faulty measuring cup that gives incorrect measurements for your recipe.

4. **Dirty Air Filter**: A clogged air filter can prevent sufficient airflow, leading to reduced power. It’s like trying to drink through a filter that’s too dirty.

#### Repair Steps

1. **Safety First**: Disconnect the battery to avoid electrical issues.
2. **Remove Air Filter**: Take off the air filter cover and remove the filter to access the intake tube.
3. **Disconnect the Air Intake Tube**: Loosen the clamps securing the tube to the air filter box and throttle body. Gently pull the tube out.
4. **Inspect for Damage**: Check the tube for cracks, holes, or significant wear. Inspect the MAF sensor for dirt or damage.
5. **Replace or Clean Components**: If any component is damaged (like the intake tube or filter), replace it. Clean the MAF sensor with a special cleaner if necessary.
6. **Reinstall**: Place the new or cleaned components back, ensuring all connections are secure and tight.
7. **Reconnect Battery**: Once everything is back in place, reconnect the battery and start the engine.

### Conclusion

Understanding and maintaining the air intake system is vital for your Jeep Wrangler TJ’s performance. Regular checks can prevent problems and ensure your engine runs smoothly.
rteeqp73