everytime i drive and it shifts into overdrive my steering wheel has a vibration to it i dont know if anyone has had this problem before but any help would be appreciated.

 

my truck just had a steering wheel vibration/slighty side to side shimmy (read: slight)...i figured it was my swampers getting out of round so i took them to get it balanced/aligned. ended up having a bad upper ball joint bushing on my drivers side causing the vibration. the part was only liked $20

 

It could have something to do with how far into the brakedown lane you drive.

 

I had a similar problem, not sure it is the same for you since mine is 2wd. But my steering drag link bar was getting pretty loose where the Pitman arm would connect to the drag link. It started out as a slight shimmy from 45-55 mph and gradually got worse. The drag link seems to be a common issue. I also found out that I need to replace my ball joints soon.