Cause:
Excess solenoid pressure regulator valve to bore clearance may cause shift and pressure problems. All the linear solenoids are fed by this regulator valve. Shift quality depends on the amount of wear and often changes with operating temperature.
Correction:
The oversized solenoid pressure regulator valve will control the minimum and maximum pressure source for the solenoid.
In ZF6HP21/28/34 (Gen. 2) valve bodies, wear is commonly found at different areas in the pressure regulator bore. Wear at the balance end causes high pressure spikes leading to broken drums, pistons or other parts and wear at the spring end of the bore allows low line pressure and lube/TC fluid to exhaust, leading to burnt converter clutches and premature bushing failure. The Sonnax oversized pressure regulator valve kit restores valve-to-bore clearances to maintain correct pressures.
Hard-coat anodized aluminum valve resists wear
New matching spring reproduces OE function with the oversized valve
Note:
Kit is NOT compatible with ZF6HP21/28/34 (Gen.2) units.
ZF valve name: DR.REO-V. Tool Required.
Symptoms:
Cause:
Excess solenoid pressure regulator valve to bore clearance may cause shift and pressure problems. All the linear solenoids are fed by this regulator valve. Shift quality depends on the amount of wear and often changes with operating temperature.
Correction:
The oversized solenoid pressure regulator valve will control the minimum and maximum pressure source for the solenoid.
In ZF6HP21/28/34 (Gen. 2) valve bodies, wear is commonly found at different areas in the pressure regulator bore. Wear at the balance end causes high pressure spikes leading to broken drums, pistons or other parts and wear at the spring end of the bore allows low line pressure and lube/TC fluid to exhaust, leading to burnt converter clutches and premature bushing failure. The Sonnax oversized pressure regulator valve kit restores valve-to-bore clearances to maintain correct pressures.
Note:
Kit is NOT compatible with ZF6HP21/28/34 (Gen.2) units.
Contents:
SONNAX Installation Instructions