The inner-workings of a TH400 transmission are an area that can be exploited by a savvy racer to gain a performance edge, whether it’s from more power being put down to having shifts that are deadly accurate. To unlock the full potential of the TH400, adding a high-quality aftermarket valve body is critical and that’s where TCI comes in. TCI’s new TH400 Billet Valve Body is a fresh take on a decades-old design that will improve shift speed and consistency at the track or on the street.

As time has passed it has become more difficult for companies like TCI to find suitable TH400 valve body cores to modify. The price of the valve body cores has gone up significantly due to their finite supply and the price point finally reached a level where it made sense to create something new. Seeing this opportunity, TCI began with a totally blank slate to create their new TH400 Billet Valve Body to address the shortcomings of the original design.

The OEM iron valve bodies are perfect for the standard use they were designed for decades ago, however, they are highly inefficient from a performance standpoint. According to Josh Seaver from TCI, a plan was devised to remove all of these efficiency issues and create a valve body that would function better in a high-performance environment.

“With the billet body, it allows for a full redesign of the passages and let us rethink where they can go. We wanted to minimize the volume to allow the shifts to come in faster and have more radiuses that have less sharp corners and tight turns to let the fluid flow better,” Seaver explains. “Big and long runs with good passage lengths allow less fluid to flow and fill everything quicker. With less volume, we can pressurize the valve body quicker to get faster shifts.

“Valve bodies don’t want a lot of flow, just enough fluid to pressurize it as quickly as possible to be as efficient as possible,” Seaver continues. “The valve body passages are large enough to have the volume needed to pressurize quickly and make sure that the clutch packs and bands receive the proper amount of fluid to function.”

By improving the speed and consistency of the shifts in a TH400 transmission this valve body will help make tuning a car much easier. The valve body will also add consistency to the transbrake release making a car more predictable in how it will react on the starting line.

The black anodized coating that TCI added isn’t just for style, it helps this valve body last longer inside the harsh environment of a transmission.

“The black anodized coating is a hard coat anodized finish that adds a lot of hardness to increase valve bore life. With steel against aluminum, it will wear a lot quicker if any grit gets in there. With this coating added to the valve body you will wear out the manual valve before you wear out the valve body itself,” Seaver says.

The TCI TH400 Billet Valve Body is currently available in both street and race designs. You can find out more about this product right here on TCI’s website.