Rubbing sound when vehicle gets up to speed of 55 mph or higher in right front of truck. Steering is not loose. Everything appears to be tight in the handling of the truck.

C1226 Right Front Excessive Wheel Speed Variation
C1233 Left Front Wheel Speed Sensor Input Signal Missing
You could have a bad sensor on the left front wheel or bad wiring. Have it checked by a mechanic. Your anti-lock braking system is probably disabled under these conditions.

There are many stages of vibration. The most common is in the steering and USUALLY a steering dampner will correct this. However, your description is not real defined and until the technician actually experiences it, it cannot be properly diagnosed

Sounds more like a worn out right front tie rod...it is hard to feel how loose it has become while sitting on the ground...not to expensive of a repair...a free inspection at most alignment or repair shops. Hope this helps.

1. out of balance tire because it sounds speed spacific.
2. worst of all! Loose lug nuts or possibly loose spindle nut. (you will need to lift the wheel off the ground to tell)
3. worn linkages i.e. ball joints, steering linkage, anything that would allow play in the front wheels.

no its your wheels well out of balance get them looked at first fitting a damper wont stop this shimmy

I'm thinking tires. Have the balance
checked.

Vibration at 40 mph hard to diagonisis without looking at front end. Could be wheels need balancing, new wheels and rims. Loose or worn suspension items.
Bring vehicle into a tire and alignment shop. Most Sears auto center have them.
With regards to rubbing noise again hard to diagonisis without looking at the affected tire, probably a splash shield hitting the tire in reverse.
Alignment shop will find the problem.

sounds like a wheel bearing but to be sure jack up the truck and wiggle the tire from top to bottom if it moves then it is a wheel bearing

Sounds like you have air in your steering system. I would start by looking for any leaks on your steering system like hose to fitting crimps, steering pump, etc. Check your steering fluid level to make sure it is full and also look for bubbles on the dip stick. If everything looks good, start the vehicle and turn the wheels all of the way to the left and then to the right. Do this while the vehicle is in park and repeat at least 5 times. This will work out any air in your steering system. If the problem persists then the power steering pump may need to be replaced.

Vibrations while driving like you are describing can come from tires that have defects (internally broken belts) (wheel weights that have fallen off) or a bent rim (perhaps from another driver [not you :-) ] hitting a curb) Are the tires worn? Have they been balanced and rotated regularly? You report no vibration in the steering wheel.
Vibrations during braking can be warped rotors or discs (but this doesn't sound like your problem since these kind are usually felt in the steering wheel during braking).
If and only if you feel like you can do this safely,
you can try getting the car up to 55, placing the car in neutral, then switching the "engine off" but leave the "key on" (be warned the power steering will go out but the vehicle can still be steered though the steering wheel will be much stiffer) if you try this (do it perhaps in a vacant parking lot or on an empty road) and the vibration goes away with the engine off but while the vehicle is still moving, then the vibration is engine or transmission related. If this is the case you might hope for maybe a bad engine mount. Bad engine mounts can be diagnosed with the vehicle stopped as well. However, if the vibration remains with the van moving forward but with the engine off, the vibration is likely a problem with the tires or suspension. Try to provide some more info.
If you don't feel comfortable trying the above suggestion, please take the vehicle in to an ASE certified suspension and steering professional for further diagnosis.

Finally, I had a similar situation happen to me today. I was riding with a friend in their van and the vehicle started vibrating more and more around 55 mph. We stopped and carefully checked the front tires (including the lug nuts for tightness) but
found a tire defect. (it had several broken steel belts that caused a bulge in the tire and thus the vibration) We changed the tire and the vibration was gone. Good luck to you.