• Delayed Reverse
  • Burnt Reverse band
  • Direct clutch burned
  • No Reverse


Debris and constant oscillation of the inner Reverse modulator valve can create scratches or wear on the critical valve spools.


Restore hydraulic function of the inner reverse modulator valve by installing direct replacement Sonnax valve with or without the related Sonnax sleeve, depending upon original failure mode.

4R44E, 4R55E, 5R44E, 5R55E

Inner Reverse Modulator Valve
Part No. 37947-53

OE Size

You need this if... View Instructions Find a Distributor

Debris and constant oscillation of the inner reverse modulator valve in listed Ford units can create casting bore wear and scratches on the critical valve spools. This allows valuable reverse and/or EPC pressure to leak, resulting in delayed Reverse engagement, no Reverse, and a burned reverse band or direct clutch.

Sonnax inner reverse modulator valve 37947-53 is a direct replacement for unworn bores containing valves with noticeable spool scratches. For worn bores containing valves with significant scratches, this direct replacement 37947-53 valve should be used in conjunction with the sleeve in Sonnax kit 37947-11K (reaming required).

  • Direct replacement valve for use in OE casting
  • Valve can also be used with sleeve from Sonnax kit 37947-11K
  • Hardcoat anodized aluminum valve combats premature wear

If bore is unworn, use Sonnax valve to replace damaged or scratched OE valve. If excessive bore wear is detected, use Sonnax valve in conjunction with Sonnax sleeve in 37947-11K. Worn/damaged OE valves used in a sleeve will not optimally restore hydraulic function.

  • 37947 53 combo
  • 37947 53

You need this if...

A visual inspection of critical valve spools finds excessive scratches.