I just bought a 04 Ranger xlt fx4. It's got 153k on it. About a week after I bought it I started to notice a slight vibration mixed with a clunking noise when taking off from a dead stop. This is the only time it happens and it stops once I get up to about 5 mph. I was thinking bad u-joint as there is about an 1/8 inch of play in the drive shaft when I turn it by hand. Any other suggestions on what it might be? Or am I accurate on the u-joint? I'm no pro when it comes to working on trucks as this is my first truck. So i'm looking for all the help that I can get! 
