Command module wiring

You can use one of the fuel timers and set it to activate a relay after a set time such as .5 seconds. Then have the transbrake hooked to a normal closed contacts on the relay so at .5 seconds the relay activates and opens the normal closed contacts and shuts off power to the transbrake

 

I have also seen people wire the tbrake through a NC air over electric switch, hooked to the low gear air line. So when you shifted, it broke the circuit.

The circuit Mike described would work. Your transbrake circuit would go into the relay on the 30 leg, come out the NC 87a. The 86/85 circuit could be triggered by a timer. In the case of a Command Module, the timer outputs are 12v, so you would hook that to the 86, and the 85 would ground.

It's been a while since I have ran a Command Module car, but I'm assuming they still reset after 7.99 like a EM timer box does. At that point it should drop voltage to the trigger wire (86) and release the relay circuit.

Here's what you need to keep in mind - 1. make sure the relay is isolated from vibrations. It's going to be hard to find a good 5 pole solid state relay. 2. I would probably run the 86 circuit from the timer wire through a switch. If not, you're going to have to wait 8 seconds every time to reengage the tbrake. This can be problematic if you use a planetary transmission behind a converter drive.