I have 2008, 2500HD Duramax/Allison, crew cab, long bed, 4X4, with the banks Econo tune with PDA, air filter and cat back exhaust. What I have noticed in that when in 6th gear and the PDA says TCC%on = 100%, which I assume in the lock up torque converter in 100% locked but while traveling at 70 MPH at 1700 RPM, the PDA TRANS SLP say 13 – 18, which I think means the transmission is slipping 13 – 18 %. This happens no mater what level your in on the Banks. Why is the trans slipping at all if the torque in locked? Is this normal?

Thanks