In the last couple days I have developed a problem that appears to be getting worse. Anytime I'm on the gas while in gear, at any speed in any gear, the whole Jeep begins to shudder or vibrate. When I take my foot off the gas, it smooths right out. In neutral or w/ the clutch pressed in, regardless of the speed I'm travelling, it smooths right out. There is no grinding or whine that I've noticed. There is no change when turning in either direction. There is no clunking when getting on and off the gas. I've grabbed the rear drive shaft, no play or looseness detected. I see no fluids leaking. And, I have not wheeled it in a couple months (a travesty, I know) so I can't imagine I dented or warped the driveshaft.
What could be causing this vibration? I'm not driving this rig until I can fix it, b/c I'm convinced something is gonna go and I'll be stranded.