Steering "knock" feeling..
 

Recently bought 06 2500 4x4 (Laramie). Just before I got it, the previous owner put new tires on. Size: Toyo A/T II, "Open Country" LT 285/70R 17.
It drives very good and runs in a straight line. However, I am feeling a "knock" in the steering...almost like a "knuckle" feeling (sorry if that's too vague). I believe I am feeling it whether I am moving or not. It is NOT a violent thunk feeling--just a sensation other than normal. While sitting at a traffic light, I notice if I turn the steering wheel very slightly (just barely), I can feel a knocking sensation in both the steering wheel (my hands) and also (slightly) in my foot (on brake peddle).
I noticed a caption on geno's garage page near a steering shaft saying the shaft is the weakest part of the vehicle, especially if oversized tires are installed.
Question: Do I have a problem? and if so, which component is the likely culprit?

Check ball joints and hub bearings

jack up the front end and have some one turn the wheel as you watch the front end and see if you can see what is shifting/moving. if that doesnt work set the truck back on the ground and try it again.

thanks guys

Ball joints. My truck eats them. Going to be on my 4th set but this time I'm going with Carlis extreme series

Thanks; seems "ball joints" is the primary response. Question, are they difficult to change out? I've never done them on any vehicle before. Also, the "Carlis extreme"...those are the best? If so, what's a good price for them? (and where)?

Thanks again!

search around on the web and you will be able to find a video of how to change out ball joints. carlis are pretty spendy, but i think they have a lifetime warranty.

Normal ball joints will run you around 200 for uppers and lowers. Carlis cost 4x as much but do have a lifetime warranty. Dynatrac make a set that is not quite as costly. Maybe 600 and are rebuildable. I do most of my own work on my truck but I have a good mechanic who charges me 400 in labor for the swap. You need specific tools to do the job and they are a bear to remove. A man has to know his limitations. I know I can do it but it'd take me far too lomg and I have 3 back surgeries under my belt already.

How many miles on your truck ?

Bought it with 154K miles. I'm on my 3rd fuel fill up, so 156-ish.

I have a good mechanic also--I'll take it to him. I have a new water pump I also want him to put on. (I think I could do the pump, but I'll pay him to do the work.)

That's a whole bunch of miles to be on original front end parts. Do you know the maint history? If you are still on original parts you are possibly going to need wheel bearings and assorted steering components.
Honestly I can't see you still having factory stuff because your ride would be scary dangerous. Jmho

Nah, I'm at 145k mi on original front end everything except shocks, a steering box brace and a Napa reman steering box that replaced the OE one a long time ago due to it locking up.
Noticed after the 5kmi trip haulin our 2ton slide on camper that I have a little more "clunk" I can feel in the brake pedal. Everything is tight except the bjs which appear to have about the same slop in them as the last time I checked them.....like 5 years ago. A lot of that clunk goes away with lower front tire pressure.
Truck drives straight, tracks well, doesn't eat tires at all....except the back ones!
FWIW, shop talked my wife into an alignment at around 60kmi when she took it in for new tires. Didn't need one and the steering wheel has been crooked since, lol. They said the ball jts were bad back then. I don't believe it. Until it gets sloppy or starts wearing the tires funny I'm not planning on re doing them.