As the Wrench Turns

"As the Wrench Turns" is a quest you receive from Chumbucket after reaching Gastown. This quest gives you access to "Chum's Holy Wrench". It is a necessity for improving the speed at which Chumbucket can repair the vehicle. You will have to go inside a tunnel to find the Wrench. Once you pick it up, the upgrade can be unlocked in the Garage for 100 Scrap