Popping sound at high steering angle

2000 XJ with about 110K miles. Just recently, when I first drive my XJ for the day, I'm hearing a rather loud popping sound from the front when at a high steering angle and the vehicle is moving slowly. Here are the details:

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  It happens at steady high steering angle, so its not due to the steering wheel and steering assembly actively being turned.

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  Doesn't matter if its a left or right turn.

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  It goes away after a few seconds of driving.

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  My XJ had been parked in my garage for about a month or two before this started happening.

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  XJ is in RWD mode.

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  Didn't happen this morning.

I guess the most obvious culprit is the front axle u-joints, but its puzzling why its starting out of the blue. There is no obvious change in their appearance. Could it be anything else? Something in the front diff (which is stock and had the fluid replaced about 5K miles ago)?

What happens when your helper turns the steering wheel and you look/listen/feel ?

Checked the lug nuts and lug nut torque ?

How old are the u-joints ? U-joints are logical, cheap, and not very difficult or technical.

How old/what condition is the track bar ? Checked both the lower and upper fastener torque and condition ?

How old/what condition is the steering ?

Thanks for the suggestions.

The front right wheel lugnuts were at about 50 ft-lbs, so I snugged those up to my usual 75 ft-lbs. Left front were fine.

Track bar was recently beefed up with the big bolt at the axle attachment. Axle-side bushing was just replaced with a stiffer press-in JK bushing and the frame-side (which is double-shear) is 100% fine. Everything with track bar, including bracket, is tight.

U-joints are seem like the logical choice to me as well. Interesting to see no obvious indications of degradation. I'm about to perform an axle swap, so I'll toss in new u-joints at that time.