Shaking wheels

My steering wheel is rocking back and forth when I make turns at low speed. I had my son watch me turn a circle in the parking lot and he could see the wheels moving in and out as I turned. I'd like to fix this before fall. Here's where I am on the process

99xj
All TRE's are new in the steering, all are tight.
Trackbar is new, JKS all is tight there as well
New OE LCA's
Tires have 10k on them and are balanced, aired to 31psi
Normal checks for ball joints/bearings show no play.
It is not in 4x4.
PS pump/gear do not make abnormal noise. fluid is full.

Give me some ideas?

Axle shaft universals. When they start to bind they'll do that even in 2WD.

Dittos. I just replaced the two in my '96. They gave me fair warning for a few weeks, with the same symptoms. When I got them out, I couldn't believe just hoe bad they were, With the axle in the vice, I could not push the splined end up or down at all. As an added benefit, afterwards it felt like a new wheel balance. I wonder if some of the complaints aired on this sight about squirrelly front ends can trace at least part of their problems to these u-joints? I've had cheap ones last longer than a $10 part should, and had killer, bullet-proof, expensive off road units go in 30k miles. Go figure..Ray

Hmm, I replaced the right one in February, left is original. Might have to pick one up. Thanks!

Good call team! I replaced the lt. side today and the issue is resolved.