Once again, we will review the normal transbrake operation:
- You activate the transbrake solenoid in low gear when staging. The solenoid pushes the brake valve to a position in the valve body that redirects fluid.
- Fluid rushes within the transmission to apply the reverse clutch piston and reverse clutches. This locks the transmission in a 1:1 fight between low gear and reverse.
- You increase engine RPM to prepare the car for launch. The transbrake remains locked and keeps the car in place.
- You release the transbrake solenoid switch which removes fluid pressure from the reverse piston and clutches. The car now has forward movement in low gear and accelerates down the track.
If the car is moving backward any during the transbrake setting and staging process, it is likely due to one of the following problems:
- Staging at an RPM that does not supply sufficient fluid volume - OEM or weak pumps need additional RPMs to move fluid quickly and adequately to apply the reverse clutches. Increasing your RPM before setting the transbrake is the first solution to try.
- Low gear band not holding.
- The low gear band can be completely worn down which would prevent it from holding low gear
- The band needs to be re-adjusted
- The servo piston has failed, is leaking, or has broken a sealing ring
- The band adjustment screw has broken or is bent