So I put a brand new tranny together there is a DTT triple disk, full rebuild, billet input shaft and a TFOD Diesel shift kit. The transmission goes from 1-2 2-3 without a hitch but it wont go into 4th or lockup. All of the electronics in the transmission are brand new so I wouldn't think that would be it. If anyone has a clue I need my truck back can you call me at 740-505-7102 please and thanks.