I pulled the Jeep in the shop tonight to start my next upgrade or mod.
The JK’s seem to have a pretty anemic steering gearbox, specifically the sector shaft. The sector shafts have been known to shear off when running larger than OEM tires/wheels and getting them bound up when off-road. That is pretty much enough to ruin your day of fun.
For the ultimate in strength and steering ability off-road a full hydraulic system is the cats meow. Seeing as how full-hydro is not DOT approved the next best option and a very common option at that is the hydro-assist setup. This design taps into the power steering gearbox and feeds hydraulic pressure to a cylinder that has one end connected to the tie rod assembly and the other end to a bracket on the axle. This is a very good setup for those running large tires/wheels and frequently engage the front lockers and still allows very good steering. It is also less stressful on the gearbox and frame as it splits the forces between the gearbox itself and the hydraulic cylinder on the axle, actually placing more force right at the axle and tie rod and less on the gearbox. In my personal opinion this is probably the best setup for tires over 37” in diameter who wheel their rigs hard. However, also In my opinion this is the most expensive and has multiple potential failure points, as in hydraulic lines although failures are not very common.
The next setup is PSC’s new upgraded steering box. PSC advertises this setup for up to 37” tires but again in my opinion 37’s are on the bubble depending on how you wheel and if your front axle is locked or not, although I have heard of a few people even running 40’s with just the upgraded gearbox.
I am only running 35” tires and seriously doubt I will ever step up to 37’s so I wanted something that mainly addressed the weak sector shaft but if I can get a bit better steering performance at the same time it’s a bonus. For my situation I feel this PSC upgraded gearbox will be the best bang for the buck and give me exactly what I am looking for.
To compare spec’s, the difference between an OEM Jeep JK/JKU steering gearbox and the PSC are as follows; the OEM has a 70mm piston and the PSC has an 80mm piston. The OEM sector shaft is a scant 35mm in diameter vs the PSC’s 45mm sector shaft, that is 30% larger. Basically the PSC gearbox closely resembles the Dodge 2500/3500 steering gearbox.
So there is the “why” behind my upgrade now let’s get to the actual upgrade. One more upgrade I thought I would do while I have the system open and fluid drained is to add a power steering cooler to the return line. I purchased a Derale 15” oil cooler a few years ago for a different project but never used it. I will be looking for a place to mount that while I’m under the Jeep.
Here is the PSC Big Bore XD that will reside under my 2011 Jeep Wrangler
Before spinning any wrenches, I used my oil evacuation tank and pulled as much fluid out of the reservoir that I could. I figured this would be less “potential” fluid that would end up on my floor.
I removed my JKS steering gearbox support system then removed the steering column connection (where I’m pointing) then I can focus on removing the actual gearbox.
Here are the two power steering lines that need to be removed. The one I am pointing to is the pressure line.
I have collected a pretty good assortment of plastic caps and plugs over the years for situations like this. These are o-ring fittings so I capped each one after removing from the gearbox to minimize the mess and oil running down the frame.
OEM gearbox our and on the bench next to the new PSC unit ready to go under the Jeep.
Before closing up the shop for the night I cut the mounting block off of the frame from my JKS gearbox support as well as a tab from beefed up trac bar bracket. I blended the ground weld and sprayed some Eastwood Extreme chassis paint on the area to allow it to dry overnight.
Today was so nice I was able to work in the shop with the roll up doors open for the first day of the year. Freakin’ awesome!
Thanks for looking.
