C-4 Transbrake Full Manual Valve Body - BTE 421500
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C-4 Transbrake Full Manual Valve Body - BTE 421500

C-4 Transbrake Full Manual Valve Body

Shift Pattern: PRN123

BTE 421500 Kit Contains:
QTY     DESCRIPTION
One(1)   Transbrake Valve Body
One(1)   Brake Valve and Spring
One(1)   Rear Servo
One(1)   Ring
One(1)   Tap
One(1)   Solenoid

NOTE: For push in style modulator case only (not for screw in modulator), please note that this is a pro-tree style brake and the transbrake solenoid must be engaged to back up.

STEP 1 Make sure that your rear band apply piston is in good condition (soft and pliable). If not, then you must replace the piston. We recommend installing a high performance billet servo (BTE428520). Install the servo reinforcement ring on top of the rear piston cover with the 1" long bolts.

STEP 2 Set the forward clutch pack (the drum that the input shaft splines into) clearance between .015" and .025". Set the direct clutch pack (the drum that the intermediate band applies to) clearance between .050" and .075". Set the band adjustment on both bands at 3 turns for a fine thread nut or 1 and a half turns for a coarse thread nut. Tighten bands 120 inch pounds, then back off 3 or one and a half turns.


STEP 3 Remove and discard the modulator and pin. Grease tap to catch shavings and tap the modulator hole with supplied tap. Install the spring, transbrake valve and solenoid (with gasket) in place of the modulator. Please note that the spring sits inside of the transbrake valve's counter bore & the spring goes into the transmission first. Check for free movement of the transbrake valve and solenoid before installing the valve body. The transbrake valve must close the last land and open into the second land by approximately .035" when pushed in by the solenoid.



STEP 4 Install the transbrake valve body and the supplied manual valve with the correct filter that matches the depth of the pan. Make sure that the shifting linkage does not bind and move freely in all gears.

STEP 5 Use a 12 gauge wire to connect the transbrake button to a 12 volt power source. One from the solenoid connects to the solenoid and one wire to the ground.

STEP 6 This is a pro-tree style brake and the transmission must be engaged to back up.

CAUTION: When adjusting the linkage the 1st, 2nd, and 3rd gear detent must align exactly. Do not align off the park or reverse. You will have transmission failure.

Posted by Brandon Barrentine at 6:49 PM