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  • Incorrect valve body calibration
  • Missing B5 control spring
  • 2-3 Harsh
  • 3-2 Harsh
  • 2-3 Flare
  • 3-2 Flare


TCM programing anticipates spring control response in the B5 control line-up in certain vehicles. Without this spring, the calibration is mismatched and 2-3/3-2 shift issues may occur.


The Sonnax B5 control spring is a direct replacement for the OE spring and it can be added to any valve body in order to match the TCM calibration.

55-50SN, 55-51SN

B5 Control Spring
Part No. 59947-33

Also fits AW55-51SN, AF 23/33 and RE5F22A units. Only some '05-later units were equipped with a control spring in the B5 clutch control valve line-up.

Package Quantity: 5

View Instructions

Only some Aisin AW 55-50SN transmissions ('05-later units installed in Nissan and GM vehicles) were equipped with a control spring in the B5 clutch control valve line-up. Using a valve body without a spring in those vehicles creates a mismatch between the B5 line-up and the TCM calibration, often causing a harsh 2-3 upshift or 3-2 downshift. Sonnax offers B5 control spring 59947-33 as a direct replacement for the OE spring. This allows rebuilders to rebuild any suitable core for use in vehicles where the spring is required, or correct shift concerns caused by a missing spring.

  • Restores valve train response, matching the TCM calibration
  • Allows any AW55-50SN valve body to be converted to a spring type application
  • Direct replacement, no special tools required

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 33 combo
  • 59947 33