There is supposed to be some play in there, it allows for body flex and drive train flex..
If you put spacers in, you run the risk of blowing out the diffs...
I solved this problem by going to radio shack, and purchasing a $5 8xAA battery holder (holds 8 AA batteries) and clipped the springs off and inserted them on each side of the dog bones... allows the drive train to move, but keeps the dog bones centered...
works great so far..
There is still a lot of play with the cvd's in the front... that's just wear and tear. Redcat does sell a CVD rebuild kit..