I have a 1998 K2500 with the 5.7 and 3.73 gears. For me it is geared to low with 3.73 gears. I use it for a daily driver and it takes getting it to 50 mph before it fully shifts to overdrive and T/C locked. Is there a tuner that I can use to change the shift points or do I need a custom tune to do it. Thanks for the help in advance.