Steering Gearbox Upgrade for Jeep Wranglers

Limitations of the Factory Gearbox

The factory steering gearbox on TJ, JK, and JL Wranglers was designed for stock tire sizes. When you increase tire size — especially to 35 inches or larger — the steering system has to work harder to turn the bigger tires. The factory gearbox can feel vague, with excessive play in the center position and insufficient assist when turning at low speeds or off-road. The steering wheel may have noticeable free play before the tires respond.

The factory gearbox's internal valving is calibrated for stock tire sizes and vehicle weight. The recirculating ball design is durable but has inherent looseness that gets worse with mileage. As the internal components wear, the steering play increases. A worn gearbox can make a Wrangler wander at highway speeds and require constant steering corrections, which is exhausting on long trips.

Adjusting the Factory Gearbox

The factory steering gearbox has an adjustable sector shaft preload that can reduce some of the play. This is a temporary fix that works best on gearboxes with moderate wear. The adjustment screw is on top of the gearbox, and turning it clockwise reduces play. Adjust in very small increments — an eighth of a turn at a time — and test drive between adjustments. Too much preload will make the steering stiff and will not return to center properly.

If the gearbox has significant wear, adjusting the preload will not fix it. The internal components are worn beyond the adjustment range. At this point, replacement or rebuild is needed. A rebuilt factory gearbox from a quality rebuilder like Redhead or Blue Top is a popular upgrade that provides tighter internal clearances than the original.

Aftermarket Upgrades

For Wranglers with 35-inch tires or larger, an upgraded steering gearbox from PSC or AGR provides significantly more assist and tighter internal tolerances. These gearboxes have larger internal components, heavier-duty valving, and tighter clearances. They provide more steering assist at low speeds and better on-center feel at highway speeds. The improvement is dramatic compared to a stock gearbox.

A hydraulic assist steering system is the ultimate upgrade for serious off-road use. This adds a hydraulic ram that assists the steering box, providing massive steering force at any speed. Hydraulic assist is popular on Wranglers with 37-inch or larger tires and on vehicles used for rock crawling where steering forces are extreme. This is a significant upgrade in cost and complexity but delivers unmatched steering control.

Bottom Line

If your Wrangler's steering feels vague or has excessive play, start by adjusting the factory gearbox preload. If that does not help, a rebuilt gearbox from Redhead or Blue Top is a cost-effective upgrade. For Wranglers with 35-inch or larger tires, an aftermarket gearbox from PSC provides much better steering feel and assist.

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