I had the problem with it pulling to one side, my problem was that the rear left i think ( this was over a year ago)
it was toeing in a bit more that the right. My Mate had this and the part that holds the wishbone pin in under the diff housing was cracked slighly so the wishbone wasnt straight. But in 2yrs of having the same TC3 with the adition of almost every Fastrax upgrade
i have never had any binding at all
But they do take a while to set up just like MManson said.