it feels like my steering wheel is moving?

get that into the shop as soon as you can before you lose your front axle or your steering goes out completely. At least that's what I would do

 

It sounds like you have front u-bolts, shackles, end pins, or center bolts broken or loose. Get it checked thoroughly NOW before the axle folds up under the truck.

 

What brand and model?

 

Sounds to me like a wheel alignment. That'll put your springs in a bind causing a low bang as they shift.
Any unusual steer tire wear? Most likely you'll see the inside tread wear slightly.
Mismatched tires on the drives?

If you never had one done, it's just the opposite of a car wheel alignment. They line the drives up with the steers.

Then again you could have the above issues. Hard to diagnose over the computer.
You need to get in the shop regardless.

 

the guys are right--sounds exactely like a front spring issues

 

since you say its a Ryder truck, write it up, drop it off, get a spare truck, go about your business.

this is all we can actually tell you. when in fact, you should have just done this. as NO ONE HERE can actually diagnose your problem from just reading about it.

 

I had the same problem with my Vulva and it was the drag link and tie rod ends.