Band Servo

BAND SERVO
Preinspection





Band servo operation
1. Apply compressed air through the oil passage as shown.
2. Verify that the piston stem moves toward the brake band.

Air pressure: 390 kPa {4.0 kgf/sq.cm, 57 psi} max.

3. If not, the D-rings or the O-rings may be damaged or the piston assembly may be sticking. Inspect and replace as necessary when assembling replace as necessary when assembling.





Disassembly / Inspection / Assembly
1. Disassemble in the order shown in the figure, referring to Disassembly Note.
2. Inspect all parts and repair or replace as necessary.
3. Assemble in the reverse order of disassembly, referring to Assembly Procedure.

Disassembly note





Piston and servo piston retainer
Remove the piston and servo piston retainer from the transmission case by using a plastic hammer.





4GR band servo piston
1. Block one oil hole of the Fourth gear servo piston retainer and the center hole in the Fourth gear band servo piston.
2. Apply compressed air through the other oil hole in the Fourth gear servo piston retainer to remove Fourth gear band servo piston.

Air pressure: 390 kPa {4.0 kgf/sq.cm, 57 psi} max.

3. Remove the D-ring from the Fourth gear band servo piston.


Inspection
Return spring








1. Measure the spring free length.
2. If not within specification, replace the return spring.


Assembly procedure





1. Apply ATF to new O-rings and install them onto the servo piston retainer.
2. Apply ATF to new D-rings and install them onto the band servo piston.





3. Apply ATF to the servo spring retainer and retaining ring (large). Assemble them in the band servo piston.





4. Assemble the band servo piston, piston stem, return spring, and spring retainer.
5. Install the retaining ring (small).





6. Apply ATF to the band servo piston assembly.
7. Apply even pressure to the perimeter of the piston, and install it into the band servo retainer.





8. Apply ATF to a new D-ring and install it onto the Fourth gear band servo piston.





9. Apply ATF to the Fourth gear band servo piston.
10. Apply even pressure to the perimeter of the piston, and install it into the-transmission case.





11. Install return springs A and B.
12. Apply ATF to the piston assembly.
13. Apply even pressure to the perimeter of the piston assembly, and install it into the transmission case.





14. Apply ATF to the band servo retainer and a new gasket, and install them on the transmission case.





15. Tighten the bolts evenly and gradually in the order shown.

Tightening torque: 6.9 - 8.8 mm {70 - 90 kgf.cm, 61 - 78 in.lbf}








16. Verify servo piston operation by applying compressed air through the oil holes as shown.

Air pressure: 390 kPa {4.0 kgf/sq.cm, 57 psi} max.