Funny enough the LS is the first AWD car I've ever owned. Perhaps this is normal behavior, but when I turn the car full-lock and start moving, I often feel a little resistance or a little bit of a vibration feel through the steering wheel. I've been in a truck or two before where the 4WD system binds, and the LS is nothing like that. But it does have kinda the feel of beginnings of binding to me. Like things are starting to stick a little bit. No tire scrubbing or grinding or anything. Just an odd feeling through the steering wheel. Every other vehicle I've owned, front or rear drive, none have ever displayed this sorta odd binding feel when turning the car tightly.

Is this just inherent in AWD systems? I have driven just once or twice a RX and NX with AWD but probably never enough in tight parking situations that I would have felt something like this. Those are also front-drive based vehicles, so maybe they act differently? Would one feel the same thing at full lock in an Audi with Quattro, or an AWD BMW for example?

I'm curious more than anything, but also still dealing with a chirping noise in the car that the dealer cannot diagnose. Loudest under light acceleration but also present when coasting and gets louder turning one direction and disappears when turning the other direction. So I'm also curious if maybe something is wrong with a CV axle/joint. Maybe if the slight feeling of binding is abnormal and this chirping that seems to be coming from the wheel well, wondering if the CV could be bad.

 

Not sure how many miles you have but what you described sounds like the fluid in the center differential needs to be replaced. I did the fluid in my LS 460 AWD and felt smoother at the extreme ends of steering input afterwards. You may read up in the LS460 forums as the LS500 (from what I can tell) is very similar. Center LSD differential with an open front and rear differential. The only other thing I could imagine is that one of the CV shafts are contacting suspension members or your frame. But id imagine that Lexus built in enough space by design to make that impossible. You'd just need to look at the front CV axles on a lift at the maximum steering angles.

edit: the shuddering is because of the difference the front wheels are trying to travel (longer) is different than the rear wheels (shorter) and the old fluid isn't allowing for it to slip enough so it's binding at the center differential.

 

Appreciate the input. It really is pretty minor, just not a feeling I had before. I suspect it is OK. Being new car I can't imagine I need new fluid already....

I'm nearly certain there is no interference with CV shafts or anything.

Probably totally OK but an odd sensation if not used to it.