I have a 48' EF my father restored with the original drive train (5 speed) it tops out at 30MPH. I also have a couple other e model truck I plan to restore one is an EG with 2 sticks. One to the main transmission, the second one goes to a aux. transmission further back. (I am assuming high/low for each gear). My question is this: With the aux transmission does this change the gearing to increase the top speed?