I recently replaced the manual steering gearbox in my recently purchased 95 YJ. It has a 4" lift with 31" AT tires. It had about a 1/4" turn of slop in the steering. Replacing the steering gearbox fixed about half of that. The gearbox itself still appears to slightly flex. It does have a steering stabilizer shock.
I am contemplating adding a steering gearbox stabilizer. What other improvements (including new ball joints) could a person do to stiffen up the loose steering? Or is this normal for a YJ?
The 4" lift is hurting your steering for sure. The YJs have a pretty flawed steering setup that doesn't really show its inherent flaws in stock form. YJs have what is known as "Inverted-T" Steering which is a tie rod that goes from steering knuckle to steering knuckle, and then a drag link from the tie rod to the pitman arm.
In stock form, the YJ is pretty low and the drag link doesn't have much angle to it. The YJ also has a stock track bar which minimizes any bump steer in stock form, even though yes it is a leaf spring vehicle, and doesn't "need" a track bar. It can still benefit from the track bar for steering feel though. Especially for holding the axle still under steering forces. The masses won't tell you it but leaf springs mounted to rubber or poly bushings don't exactly hold up to steering forces very well, especially when the springs are tall (4" lift" and the steering has more leverage against them. The leaf springs start to give and rock back and forth before the steering can move the wheels.
But, back to the steering linkage itself. Inverted-T steering's flaw is the dead spot during it's operation. By design, tie rod ends are allowed to pivot on the ball and socket design that they are made from. This means that you can sit there and push the tie rod and it will move around even though it is secure. This is perfectly normal. The problem comes when you mount the damn drag link to the tie rod. Now, you are adding steering input to the drag link which pushes on the tie rod, and then the tie rod "rolls" to the limit before steering the wheels. Then when you turn the steering the other direction, the tie rod rolls again to the opposite limit of it's travel. You don't feel much of this in stock form because the drag link angle is pretty low.
So then you add a 4" lift which brings the drag link mounting at the pitman arm 4" higher than stock. This has a HUGE effect on steering. The drag link that was originally almost flat is now sitting really tall and angled. The angle makes the tie rod roll effect way worse. You can install a drop pitman arm which helps some, but unless it's a pitman arm with a drop 4" longer than stock, then it won't fix the problem completely. And, nobody I know makes a 4" drop pitman arm. Usually they have like a 1-2" drop compared to stock. So it only fixes the problem halfway. You can get super tall pitman arms from I think a Grand Cherokee, but that puts a lot of leverage against the stock steering gear box on a YJ and I've seen them crack the shaft the pitman arm bolts to as a result of that.
So really, there are a few solutions that fix the problem mostly, each with their own pros and cons. The first is the WJ knuckle swap, which I'm not even going to get into because it's just too much work for me to recommend. I did it on mine. Likely wouldn't ever do it again and I'm planning on getting rid of it.
My go-to would be lower the lift to a Rubicon Express 2.5" and use their 0.5" lift shackles. Then run a 1.25" Body Lift. Add a set of TJ flares and keep the bump stops in check and honestly it should fit 33's or 35's perfectly fine. A drop pitman arm would probably fix most of any steering vagueness felt by the lift. I would then replace all tie rod ends, ball joints (go with Spicer), and maybe change the steering shaft bearing. I use the Wolff engineering bearing, works well.
You could also go the 2.5" lift route and get a one-ton steering kit from Ruffstuff. it isn't perfect either as it's still Inverted-T, but you can mount the tie rod ends on top of the knuckles, which can get the drag link pretty much flat with a stock pitman arm and you'll be back to mostly stock steering feel. 2.5" springs will be small enough arch that you should have decent feel without a track bar. The stock track bar is only worth keeping on stock suspension, it's a really short design that doesn't work well with any suspension lift. That's what makes 4"+ lift such a bitch to fix.
The moral of the story is that YJ steering is pretty bad, lifts make it worse, keep your lift modest and possibly use a drop pitman arm or over the knuckle steering kit to fix most of the problem with the angles. It will always have some dead spot unless you install a crossover conversion, like the teraflex knuckle or the WJ knuckle conversion, but those both open whole other cans of worms. It's a mess.
Your steering gear should not be "flexing", I don't really know what that means. A video of it might help. Sometimes the frame may crack at the mount and allow flex. Maybe you're cracked or something somewhere and need to come up with a new way to fasten your steering box. I'm not sure.
