1998-2000 Montero Steering Gear Box: Diagnosing Leaks, Play, and Wander

Understanding the Montero Steering System: Gear Box vs. Rack

It's important to know that the 1998-2000 full-size Mitsubishi Montero (also known as the Pajero Gen 2/2.5) does not use a steering rack. It is equipped with a recirculating ball steering gear box. This system is known for its strength and is well-suited for off-road use. However, it has more moving parts than a rack and pinion setup, which means more potential points of wear that can lead to common issues like steering 'play' or looseness.

Symptoms of a Failing Steering Gear Box

Diagnosing a steering issue requires looking at several components, but here are the signs that point specifically to a worn or failing steering gear box.

1. Excessive Steering Play or 'Wander'

This is the most common complaint. You'll notice a 'dead zone' when the steering wheel is centered, where you can turn the wheel slightly in either direction before the wheels actually respond. This forces you to make constant small corrections to keep the vehicle driving straight, a condition often described as 'road wander'. While worn tie rods or a bad idler arm can contribute, significant play often originates inside the gearbox itself due to worn internal gears.

2. Power Steering Fluid Leaks

Leaks are a clear sign of trouble. Fluid may seep from several places:

• Pitman Arm Seal (Output Shaft Seal): This is a very common leak point. You'll see power steering fluid dripping from the bottom of the steering box where the Pitman arm connects.
• Input Shaft Seal: Fluid leaks from where the steering column connects to the top of the gearbox.
• Adjuster Screw: Some owners report leaks from the threads of the top adjuster screw, which can sometimes be fixed by tightening the lock nut.
• Hose Fittings: The high-pressure and return lines can leak at their connections to the box.

The power steering fluid should be checked. In many older Mitsubishi vehicles, the recommended fluid is DEXRON or DEXRON II/III type Automatic Transmission Fluid (ATF), which is typically red. If the fluid is low, dark, or has a burnt smell, the system needs attention. Foamy or milky-looking fluid indicates air is in the system, likely from a leak.

3. Grinding, Clunking, or Jerky Steering

A clunking noise when turning could be a sign of a problem within the steering gear. Jerky or uneven steering effort, where it feels easy one moment and hard the next, also points to internal gearbox issues. A whining or groaning noise that gets louder when you turn the wheel is often caused by a power steering pump that is low on fluid (due to a leak) or is failing.

Known Issues, TSBs, and Recalls

Searches for recalls and Technical Service Bulletins (TSBs) for the 1998-2000 Mitsubishi Montero's steering system on the NHTSA database did not reveal any specific recalls for the steering gear box itself. Most steering issues on these aging vehicles are related to wear and tear of the mechanical components and seals rather than a manufacturing defect. One TSB found was for a much newer Outlander model and is not relevant to this Montero.

Diagnosing the Problem

Before condemning the steering box, it's critical to inspect the entire steering and suspension system. Worn tie rod ends, ball joints, and especially the idler arm can cause symptoms similar to a bad steering box.

1. Check for Play: With the engine off and a helper, lay safely in front of the vehicle. Have the helper slowly rock the steering wheel back and forth within the 'play' range. Watch every connection point: the Pitman arm, idler arm, and all tie rod ends. Any visible slop or clunking indicates a worn part that should be replaced.
2. Isolate the Gear Box: If all other components are tight, but the input shaft of the steering box turns while the output shaft (and Pitman arm) does not, the play is internal to the gearbox.
3. The Adjuster Screw: The top of the steering box has an adjuster screw with a lock nut (often 17mm). This can be used to remove a small amount of slack. However, this is a last resort after confirming all other components are good. Over-tightening this screw can cause the steering to bind or fail to return to center after a turn, which is dangerous. If the screw is already tightened to its maximum, the box is worn out and needs replacement.
🎬 Watch this video on adjusting the Montero steering gear box

Buying a Used Steering Gear Box

For a vehicle of this age, a quality used OEM steering gear box is often a more practical and reliable choice than a cheap aftermarket unit. Here’s what to look for:

• Verify Compatibility: Ensure the part is from a 1992-2000 full-size Montero, not a Montero Sport. Cross-reference OEM part numbers like MB636331, MR112835, MR112839, or MR267974.
• Physical Inspection: Check for any cracks in the housing. Look closely at the areas around the input and output shaft seals. If they are perfectly clean on an otherwise dirty part, they may have been wiped down to hide a leak. Ask the seller about the mileage of the donor vehicle; lower mileage is always preferable.
• Shaft Play: Try to wiggle the input shaft and the splined output shaft (where the Pitman arm mounts). There should be no side-to-side play. Rotational play is what the adjuster screw is for, but excessive play suggests significant internal wear.
• Core Value: Many remanufactured units require you to send back your old steering box as a 'core'. A used part does not have this requirement, simplifying the purchase.

Cost of Replacement

Replacing the steering gear box is a significant repair. The part itself can be expensive, especially from the dealer.

Replacement Overview & Related Parts

Replacing the steering gear box is a job for an experienced DIYer or a professional shop. It requires heavy-duty tools, including a Pitman arm puller, which is essential.

Key Steps:

1. Raise and safely support the vehicle on jack stands.
2. Disconnect the steering shaft from the input of the gearbox.
3. Use a Pitman arm puller to separate the Pitman arm from the gearbox output shaft. This can be very difficult.
4. Disconnect the power steering fluid lines. Be prepared for fluid to spill.
5. Unbolt the steering gear box from the vehicle frame and remove it.
6. Installation is the reverse of removal. New mounting nuts may be required.

Bleeding the Power Steering System

After installation, the system MUST be bled of air to prevent noise and damage to the power steering pump. Do not start the engine immediately.

1. Fill the reservoir with the correct fluid (DEXRON II/III ATF is commonly used).
2. With the engine OFF, turn the steering wheel fully from lock to lock several times. Watch the fluid level and add more as it drops.
3. Once the fluid level is stable, you can start the engine. Let it idle, and again, turn the wheel lock to lock a few more times.
4. Check for leaks and top off the fluid. The fluid should be clear, not foamy or cloudy.

Torque Specifications

Using correct torque is critical for safety. While specific values for the 1998-2000 Montero can be hard to find, general values for similar Mitsubishi trucks provide a good guideline. Always consult a factory service manual if possible.

• Gearbox Mounting Bolts to Frame: 40–47 ft. lbs. (55–65 Nm)
• Pitman Arm to Relay Rod Nut: 33 ft. lbs. (44 Nm)
• Steering Shaft Pinch Bolt: 22–25 ft. lbs. (30–35 Nm)

Frequently Asked Questions (FAQ)