I have a built waller transmission and the trans works perfectly in and around town. It runs right through all the gears but when I get on the highway it doesnt want to go into O.D. and when it does its only for a split second then it goes back into 3rd. My truck has a fast unit and it uses the b&m box to lock up the converter. Could the b&m box be causing the problem with the trans jumping back in forth while at high way speeds? Has anyone had this problem with there trans and if so what should I look for. Thnx.