I posted about this problem before and never got any helpful responses. Hoping maybe someone will know what the problem might be. I have an issue that after I drive my truck and the tranny gets warmed up and I let it idle in park for a minute or so it will start making a vibration noise that i can feel thru the floorboard and it even travels up thru the steering column slightly. I haven't noticed the noise or vibration in any other gears. The tranny seems to pull fine though while driving. Is there a solenoid for Park that may be going bad and not holding enough pressure? Any help would be appreciated as this is worrysome until I can figure out what is wrong. I don't think it is loose linkage since it is only a problem in park so far. Truck has almost 50k miles on it now.

Thanks ahead of time.