We've put together a batch of TransStim kits to use to test out transmission control devices. These simulate seven general purpose outputs, a VSS signal, a transmission temperature sensor, a switch type gear selector, paddle shift buttons, and a brake switch. The kits are priced at $65. Since neither a GPIO board nor a MicroSquirt board has a mating connector to their AMPSEALs, this uses screw type terminals and allows you to make an adapter harness.