Cause:
Pressure regulator bore wear allows fluid loss that causes erratic line pressure and poor drivability.
Correction:
Recover pressure control and renew shift quality by reconditioning the bore and installing Sonnax oversized pressure regulator valve kit.
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.
Valve is hardcoat anodized to resist wear
Sleeve is made from highly wear-resistant aluminum
Note:
Kit is NOT compatible with ZF6HP19/26/32 (Gen.1) units.
ZF valve name: SYS.DR-V. Tool Required.
Symptoms:
Cause:
Pressure regulator bore wear allows fluid loss that causes erratic line pressure and poor drivability.
Correction:
Recover pressure control and renew shift quality by reconditioning the bore and installing Sonnax oversized pressure regulator valve kit.
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 ZF6HP19/26/32 (Gen.1) units.
Contents:
SONNAX Installation Instructions