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Sonnax GM 700R4 Oversize Pressure Regulator Valve Automatic Transmission

OPT Product Code: SNX-77917-06
$48.16
Sonnax GM 700R4 Oversize Pressure Regulator Valve Automatic Transmission

Product Details


Sonnax now offers an oversized pressure regulator valve for the 700-R4, 77917-06 and the 4L60-E, 77917-07. The Sonnax valve permits pump covers to be restored to OEM specifications despite wear and leakage at the pressure regulator valve. The pump cover is reworked using the Sonnax Reamer and Guide Kit 77917-TL which refinishes and prepares the valve bore to accept the oversized PR valve. A worn OEM pressure regulator valve can be detected in two ways. The first is a dynamometer test that reveals low line pressure during boost conditions (look for 50-100 psi less than specified in Reverse). The second is vehicle symptoms such as clutch slippage, reverse chatter, and 3-4 clutch failure. Any of the above problems indicate a worn pressure regulator valve that should be replaced with the oversized Sonnax valve. Wear usually occurs at 3 locations. The most common wear areas are on either side of the decrease circuit where the double spool constantly oscillates. With these areas worn there is leakage of line pressure in boost conditions and leakage of decrease pressure during non-boost conditions. The result is twofold. First, line pressure is too low when high line holding power is needed during boost conditions (pressure can be 50-100 psi low in reverse). Second, the decrease circuit fails to effectively adjust pump output. The pump slide movement is erratic causing excess pump noise and wear. Also, line pressure is too high and uncontrollable during non-boost conditions. The last wear area is at the balance end of the pressure regulator. The result is balance oil leakage which locates the valve in a high line position. The Sonnax PR valve helps restore control over the pressure regulating circuit by eliminating leakage.

Sonnax GM 700R4 Oversize Pressure Regulator Valve Automatic Transmission

OPT Product Code: SNX-77917-06
$48.16

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