sonnax-black Facebook-color LinkedIn-color maillink printlink r_and_r_only SERVOFIX-logo-web Twitter-color VBFIX-logo-web video-logo-web warranty_only Youtube-color


  • Increased throttle required for engagement
  • Delayed Forward


Bore wear in the neutral relay valve results in leakage from the forward clutch circuit, which reduces the forward clutch apply pressure.


The Sonnax oversized neutral relay valve and spring correct circuit pressure loss and restore control of forward clutch apply circuit.

55-50SN, 55-51SN

Oversized Neutral Relay Valve Kit
Part No. 59947-35K

You need this if... View Instructions

Vehicles equipped with Aisin AW 55-50SN transmissions may suffer from delayed forward engagement and require increased throttle for engagement. These problems are caused by bore wear at the neutral relay valve, resulting in loss of clutch engagement pressure. This can be fixed with the Sonnax oversized neutral relay valve kit 59947-35K. The Sonnax valve kit restores clutch pressure, which will eliminate delayed engagement and the need for increased throttle.

  • Hard-coat anodized aluminum valve for increased wear resistance
  • Tighter fit to bore than OE for better sealing
  • F-59947-TL34 tool kit can be used for both 59947-34K and 59947-35K oversized valve kits
  • Valve
  • Spring
  • End Plug

Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.

Aisin AW 55-50SN Valve Body Layout

Aw55 50sn vbl thumb
  • 59947 35k combo
  • 59947 35k

You need this if...

A vacuum test at the ports indicated fail to hold at least 16 in-Hg, or if visual wear is detected

  • 59947 35k test