4R70W Main Pressure Regulator Valve, 1996-Up 76948-09
A common complaint in vehicles with an AOD-E/4R7OW transmissions is low line pressure or throttle sensitive buzz, especially when hot. This is often caused by a worn main regulator valve. The valve frequently wears on the boost spool diameter and allows EPC (electronic pressure control) oil to leak to exhaust. This leakage results in poor line rise. When the oil temperature increases, the oil becomes less viscous and more leakage occurs.
Another common complaint with these transmissions is poor reverse boost, often the result of a worn pressure regulator boost sleeve. The sleeve should be checked while replacing the main pressure regulator valve. Sonnax offers a replacement pressure regulator boost valve and sleeve kit.
Vehicles with 4R70E, 4R70W, 4R75E, 4R75W and AODE transmissions often have erratic line pressure, poor line rise and/or throttle-sensitive buzz. This can result in harsh or soft shifts and band/clutch failure as well as other driveability concerns. Worn pressure regulator valve spools allowing pressure escape are a common problem in these units. Installing Sonnax main pressure regulator valve 76948-09 restores normal line pressure operation in all ranges.
If bore is excessively worn, install Sonnax oversized pressure regulator and boost valve kit 76948-17K.
Sonnax valve replaces both styles of OE valve.
- Hardcoat anodized aluminum valve combats premature wear
- Annular grooves help center valve in bore to reduce side-loading
NOTE:’91–’95 PR valve and ’96-later PR valve designs are not interchangeable. For ’91–’95 PR valve, see 76948-01.