Mercedes 722.9 transmissions may exhibit line pressure and converter-related problems due to excess wear in the working pressure regulator bore. Deterioration between the line and sump ports allows fluid loss that results in reduced lube flow and low line pressure. Wear at the balance end can cause high line pressure and harsh shifting. Reconditioning the bore and installing Sonnax oversized working pressure regulator valve 88740-01 restores hydraulic integrity for revived line pressure in all ranges.

• Hardcoat anodized aluminum valve combats premature wear
• Lengthened critical spools for added stability and wear prevention
• Annular grooves help center valve in bore to reduce future side-load wear