Have a 4x4 and in 2wd when I come to a stop the truck vibrates so since it snowed and I put in 4WD and realized there is no vibration at all and brakes smoothly coming to a stop in 4WD.

 

Are you sure it isn't your ABS actuating that feels like a vibration?

 

I'm not sure I never had an ABS issue with a vehicle so I'm don't know how I could tell. The emergency brake light is on though and won't turn off.

 

First, when you first turn on the key for your vehicle it will do a bulb check of all the warning lights, if one of them says ABS, you have it.
Second, if your ABS is activating (like when you're braking on ice) you will feel the brake pedal flutter/vibrate if you press the brakes hard enough to be locking up tires.
Third, if you put it in 4x4 the front and rear wheels are locked together through the t-case and it will be much harder to lock up tires, so the ABS won't activate nearly as often or as easily.