LonestarCTD

I was driving earlier this week when I was approaching a stoplight and it was yellow, so I did the logical thing and punched it to get past it before red. Well, it made it across before red but I heard what sounded like I ran over something. Ok, that was the first time but I didn't realize I had a problem. Now, today, I was driving down the Interstate and there were cars between me and the exit ramp, so I did the logical thing and punched it to get ahead of them and get into the exit lane. Well, it made it fine but just after I punched it, I heard a whine/grind sound from what I believe was the tranny. A bit later, going around a long turn, I punched it a bit again and there it was....this whining, almost grinding sound from the tranny. Later in the day, just driving around surface streets looking for a certain address, I noticed that when I would take off from a stop sign, if I gave it a bit more than normal throttle, I would hear that same whining/grinding sound from the tranny. It would continue, kinda like something was loose or misaligned, but nothing popping or anything...just this whine...whine....whine...and I could hear gear teethlike sounds until completely stopped. Then, if I attempted to take off at a normal pace, without really pushing her, she took off fine and no more whine. Shifted through the gears all the way 2nd to 5th with no problems. But, in ANY gear, if I had to push her hard, there is the whine again...whine...whine...whine...like something is loose...the whining keeping somewhat in tune with the engine revs but it was unaffected by my pushing the clutch in or releasing it. The whine was almost like it was keeping at the same speed as the driveshafts or differentials. I came to a complete stop and the whining stopped. Then I started up again, no problems. Drove her home about 55 miles without a hitch. At higher speeds, 55-65....smooth as silk although I didn't hammer down on it for fear of problems. When I arrived in my hometown, I was crossing traffic at an intersection and this dually was coming pretty quick from the other direction, so I gave it some throttle to try to get across fast....there was the whine again...whine...whine.....whine.........whine..... ...........whine...slowing until I stopped completely. I started up and she drove home normally. Over the lifetime of the truck, I have tried hard not to abuse this truck. I have engaged in the occasional red light drag against a ricer, but have NEVER pulled a sled or drag raced at a strip, etc. I pull a 5th wheel trailer now and then and have never had a problem or heard anything like this until now. I am completely LOST as to what this is. If anyone has had a similar situation or symptoms...please provide your input. Any and all replies would be greatly appreciated.