TH400 valve body for 1965-1990, OEM and ready to install. Ships fast from the USA.
A transbrake lets you load the engine against the converter at the line without the truck or car creeping forward, and a reverse pattern shift gate keeps hard acceleration from bouncing the lever into neutral - this kit builds both into one valve body for the TH400, covering 1965-1990 applications, so a race or high-performance build gets manual control over every shift point instead of GM's stock shift logic.
A transbrake works by holding the TH400 in first and reverse at the same time through a dedicated solenoid circuit, which locks the output shaft against the engine so you can bring the engine up against the converter with the brake off and the car staying still, then release the button for an instant, clean launch into first gear. The reverse pattern part of the kit flips the manual shift gate so that pulling the lever under hard acceleration moves it toward a higher gear rather than toward neutral or park, which is what a forward-pattern shifter can do if it gets bumped by vibration at speed.
Because this kit replaces the stock valve body's shift logic entirely, confirm your case casting and governor cover against your current unit before ordering, and make sure your shifter and wiring can support a transbrake button and a reverse-pattern gate - this is not a drop-in swap behind a stock column shifter. Our TH400 valve body problems and testing guide covers how to check your current valve body's condition and line pressure before deciding whether a full manual transbrake kit or a simpler shift-improver kit is the better fit for your build.
The TH400 covered here spans 1965-1990 and was used across GM trucks, motorhomes, high-performance cars and even Jaguar and Rolls-Royce applications, but a reverse pattern transbrake kit is built for a performance or race application with an aftermarket shifter, not a stock daily driver. Match the case casting and bolt pattern on this kit against what you are pulling, and confirm your application's governor setup, since some of what we stock removes the governor entirely in favor of full manual control. The TH400 parts collection has the rest of what we carry for this transmission.
Wire the transbrake solenoid to a dedicated button on the shifter, not through the existing reverse-light or neutral-safety circuit, and route it so the brake only arms with the shifter in the staging position. Refill with Dexron ATF and verify pressure at both the transbrake circuit and normal drive pressure before making a pass. A dedicated cooler is close to mandatory on a transbrake-equipped TH400, since repeated staging builds heat the stock cooling path was never designed around, and pairing this with a master overhaul kit covering fresh clutches and steels gives the new valve body a rebuilt unit to work against instead of worn friction material.
| Transmission | TH400 |
| Year Range | 1965-1990 |
| Condition | Remanufactured / updated |
| Shipping | Ships from the USA |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It locks the TH400's output shaft by holding first and reverse at the same time through a dedicated solenoid, so you can load the engine against the converter at the line without the car creeping, then release the button for an instant launch into first.
A reverse pattern gate moves the lever toward a higher gear instead of toward neutral or park if it gets bumped under hard acceleration, which a stock forward pattern shifter can do at the wrong moment.
No - a transbrake needs a dedicated button and wiring, and a reverse pattern gate needs an aftermarket shifter built for that pattern. This is a manual-control racing setup, not a stock replacement.
It covers the TH400 as used from 1965-1990, but match your case casting and governor setup against this kit before ordering, since some kits remove the governor for full manual control.
Dexron ATF, and verify both transbrake circuit pressure and normal drive pressure before making a pass.
A dedicated cooler, since repeated staging builds heat beyond what the stock cooling path handles, and a master overhaul kit with fresh clutches and steels if the unit behind this valve body hasn't been rebuilt.
