Symptoms:

  • High line pressure
  • Harsh shifts
  • Hydraulic buzz
  • Low line pressure
  • Soft shifts
  • Clutch failure
  • Band failure
  • 2-3 Squawk
  • 2-3 Shudder

Cause:

Continuous oscillation of the pressure regulator valve causes valve body bore wear, which results in line pressure irregularities and valve instability.

Correction:

Sonnax oversized pressure regulator valve allows the valve body bore to be reamed to eliminate the wear while the anodized valve has extended spools to provide more stability and better wear resistance.

4T40-E, 4T45-E

Oversized Pressure Regulator Valve
Part No. 33886-02


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The continuous oscillation of the pressure regulator valve in GM 4T40-E and 4T45-E units wears the valve body bore. If severe wear occurs at the balance line circuit, the pressure regulator valve won't stroke to reduce line pressure and feed the converter/lube circuits. This can result in high line pressure, harsh shifts, reduced converter pressure and loss of lube. Severe wear at the other pressure regulator valve circuits can allow line pressure to exhaust or go to decrease, resulting in lack of pump inlet control, high or low line pressure, soft or harsh shifts and burnt clutches and bands. Sonnax oversized pressure regulator valve 33886-02 allows the valve body bore to be refurbished and the hydraulic integrity restored.

  • Hardcoat anodized aluminum valve combats premature wear
  • Additional spool with flats at the decrease circuit provides additional valve stability and prevents line pressure leakage
  • One valve works in both the early and late OE applications

The Sonnax valve mimics the design of the 2000-later OE valve, but may be used in 2000-earlier valve bodies as well. The 2000-earlier pressure regulator valves had an internal cross drill to allow line to feed balance line at the end of the valve. In 2000, the cross drill was eliminated from the valve, and the spacer plate changed. If the Sonnax oversized valve is used in the 2000-earlier valve bodies, a slight modification to the spacer plate and gasket will be necessary.

  • 4T40-E, 4T45-E Oversized Pressure Regulator Valve 33886-02
  • 4T40-E, 4T45-E Oversized Pressure Regulator Valve 33886-02