Electric transbrake solenoid for GM TH400 full-manual and transbrake valve bodies, 0.200 in stroke, to hold the car on the line against the converter.
The TCI 221300 is the replacement electric solenoid that operates the transbrake in a GM TH400 (Turbo 400) valve body. It carries TCI part number 221300 and has a 0.200 inch stroke. It is the solenoid used in TCI's TH400 transbrake and reverse-pattern full-manual valve bodies.
When you press the transbrake button, the solenoid applies reverse and low at the same time so the transmission holds the car against the torque converter while you stage and build the motor up on the line. Let go of the button and the solenoid drops out, releasing the brake and launching the car. Since it is the one moving electrical part in the transbrake circuit, cycling it at high current every pass is what eventually wears it out.
If your transbrake has turned lazy - slow to release, letting the car creep or leave early, or not holding at all - the solenoid is usually the first thing to check before you tear into the valve body. Dropping in a fresh 221300 brings back a crisp, repeatable release without pulling the whole unit. Most racers running a TH400 transbrake keep a spare in the trailer, because a burned solenoid ends the day.
| Part Number | 221300 |
| Fits | GM TH400 / Turbo 400 (TCI transbrake & reverse-pattern valve bodies) |
| Stroke | 0.200 in |
| Type | Electric transbrake solenoid |
| Brand | TCI |
