Oil slinger and a bad idea
 

Last night I did something stupid, I found the source of a rattle that was driving me nuts. The drive shaft in my truck has was looks like an oil slinger that faces the carrier bearing. The slinger was already beat half to death and anything but round so to stop the noise I took a pair of pliers and gave it a little bend to minimize the rattling around. I never would have guessed that it would throw off the drive shaft balance but at about 50 MPH I can definitely feel the vibration. Live and learn I guess now I'll have to straighten it out again when I get home.