P0733 — Incorrect transmission ratio in gear 3

P0733: Incorrect transmission ratio in gear 3 — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

The reported speed relationship does not match the expected ratio for gear 3. Ford documents comparison of commanded ratio with valid input/output speed information. This is a measured operating result, not proof that a particular solenoid or the entire gearbox needs replacement.

Affected system: Transmission gear-ratio monitoring

Symptoms

  • An engine/transmission warning can accompany the recorded gear 3 ratio mismatch.
  • A service-transmission message may appear; the precise display depends on the vehicle.

Possible causes

  • Unreliable turbine/input, output or wheel-speed data must be ruled out before trusting the calculated ratio.
  • Internal transmission slip or wear, especially when fluid examination shows heat damage; a code alone does not establish wear.
  • Vehicle-specific selection misalignment: GM bulletin 18-NA-083 describes the TRCM coupling on specified Buick/Cadillac applications, not all transmissions.

What to check

  • Save the full scan and event data for P0733; identify the transmission and whether the mismatch occurs in gear 3 alone or several gears.
  • Check accompanying input/turbine-speed, output-speed and selector faults before evaluating the ratio; Ford documents valid speed inputs as a prerequisite.
  • Have fluid level and condition checked by the prescribed vehicle-specific procedure. Burnt odor or dark overheated fluid calls for further investigation, not an automatic flush.
  • Compare commanded gear 3 with trustworthy input and output speeds under the manufacturer monitor conditions. Do not copy Ford example thresholds to another gearbox or test a slipping vehicle unsafely.
  • For a VIN/transmission covered by GM 18-NA-083, a qualified technician can assess TRCM coupling alignment. This historical example is not an instruction to adjust every selector.
  • Confirm the root cause before replacing parts or resetting adaptations. Stop safely and arrange assistance if the vehicle loses drive or cannot maintain predictable engagement.

Also written as: P0733-00, P073300, PO733 (some scan tools add the fault-type byte, e.g. -00).