My t45 does the exact same thing, but in second gear. I was told that it might be a bent shift fork. I dunno, taking it to get an estimate next friday the 10th. If it's more than $500, then I'm going w/ a t56 and waiting another year for my vortech. Is there anything else, besides the driveshaft and crossmember and fluids of course, that I'll need? Will the computer need to be reflashed or anything, or is it just a bolt on sorta thing?