I have a 99 ecsb silverado 2wd I have a vibration at take off and around 70mph. I thought it might be the carrier bearing so I went under the truck and pulled the driveshaft from side to side. The shaft has about 1/8" or maybe a hair more. I wasnt really putting a whole whole lot of pressure on it. Is 1/8 to 3/16 flex normal?

 

It will move some, that is probably a normal amount of play.