In this week’s version of the American Powertrain Parting Shift we get to see the inner workings of the cool Liberty 5-speed transmission used in the various Gray Motorsports entries. The “tour guide” for this fun is Craig Hankinson, the team’s Car Chief. A very experienced drag racer in his own right, Hank is the right guy for the job of showing us how 10,000 RPM gear changes are made in the automotive equivalent of a meat slicer.
Hankinson also does a good job talking about how imperative that gear ratios are in pro stock. These magnesium cased wonders are pulled from the car after ever hit of the throttle and set to the side. That’s not because they break a lot, that’s because of the fact that on any given run teams will alter the gear ratios to get them down the track quicker. As he mentions, these changes are typically made at the last minute so being extremely proficient in the gear swaps and math is a job requirement! It is fun to watch Hank pull the handle and made stuff move in the transmission. Watching him do it with the bottom off is a rare opportunity for lots of people to see how it all goes down in there.
Of course we see him splashing the Valvoline oil into the trans to keep things lubed up and happy and then he puts the bottom of the unit back on. Take note at how featherlight that bottom cover is. Magnesium is pretty awesome stuff. Each one of the transmissions is $8640 from Liberty. How many do you want?