Using the F40 Transmission
Last updated: Nov 18, 2025 by Adam Doyle
One alternative to the F23 and F35 Cobalt manual transmissions is the F40 transmission found in the Buick Regal. The main benefits of the F40 are that it is a 6-speed instead of a 5-speed, it is still widely available, and it is known to be a little stronger than the F23 and F35 options.
A few Goblin V1 builders have undertaken F40 builds, but this upgrade is considered an advanced modification. The F40 does not directly fit into the standard Goblin chassis, so modifications are required to make everything work together. These changes include alterations made by DF Kit Car to the driver-side section of the engine cage along with custom transmission mounts, shifter cable mounting, tunnel cover adjustments, and different shifter hardware.
Because the modification requires chassis and hardware changes, it is a more expensive and complex upgrade. Builders choosing the F40 should expect additional fabrication and planning beyond a typical Goblin V1 build.
More details about the development and installation process can be found on the DF Kit Car forum: F40 Transmission - Will It Work?