P0735 Gear 5 incorrect ratio

5th gear ratio incorrect

P0735 in short

P0735 means that in 5th gear the transmission computer saw the input and output speeds disagree with the 5th-gear ratio, so the transmission is slipping or misreading speed. Fluid problems, valve body wear, worn clutches and speed sensor faults are common causes. Have it inspected soon and avoid towing until it is checked.

The computer compares input shaft speed with output shaft speed to work out the actual gear ratio. P0735 sets when, in 5th gear, that ratio is not what it should be. Usually this means a clutch is slipping, but a bad speed signal can also cause it.

Owners most often report P0735 on Ford trucks and SUVs, frequently while towing. Ford links it to a worn solenoid pressure regulator valve in the valve body on some 2009–2010 Escape and Fusion models.

Most likely causes

  1. Low, burnt or wrong transmission fluid

    Common general cause
    Why it ranks here
    Fluid problems are a listed cause of ratio codes because low pressure lets clutches slip.
    What would change this
    Rises if the fluid is low, dark or burnt.

  2. Worn valve body or pressure regulator valve (some Ford/Mercury)

    Supported by vehicle data
    Why it ranks here
    Ford links P0735 to a worn solenoid pressure regulator valve on 2009–2010 Escape, Mariner, Fusion and Milan.
    What would change this
    Rises on those models if the valve body has not been replaced before.

  3. Worn or damaged clutches or other internal parts

    Common general cause
    Why it ranks here
    Internal mechanical problems are a listed cause, and dealers have replaced transmissions for P0735.
    What would change this
    Rises if the transmission slips in several gears or the fluid has clutch debris.

  4. Input or output speed sensor signal fault

    Possible — needs testing
    Why it ranks here
    Sensor problems are listed because a bad speed signal makes the computed ratio wrong.
    What would change this
    Rises if speed sensor codes are also stored or the live data drops out.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Read codes from the engine and transmission modules with a scan tool that supports both, before anything is cleared.

    Low riskTool: scan tool that reads the transmission module

  2. Check for a P0735 bulletin for your VIN at a dealer or on the NHTSA site.

    Low risk

  3. Have a shop check the fluid, compare speed sensor data with commanded gear and, if needed, test line pressure.

    Best left to a shopTool: scan tool with transmission data and output controls

    Warning:Shop test. Pressure testing needs gauges and the maker's specifications.

Symptoms

  • Check engine light
  • Slipping or engine flare in top gears, especially while towing
  • Wrong gear shown on the dash
  • Engine revs but the vehicle does not move Gets more serious: stop and have it checked.

How to fix

  1. Do not clear the code before the transmission module has been read; the stored data helps the shop.

  2. Avoid towing or heavy loads until the transmission has been checked.

  3. Check the transmission fluid level and condition if your transmission has a dipstick or the owner's manual describes a check, and look for leaks under the car.

  4. Ask a dealer whether your VIN has an open P0735 bulletin or software update.

On your vehicle

Ford

  • 2009–2010 · Escape

    Supported by vehicle data

    Ford ASI-44733 links P0735 to a worn pressure regulator valve in the valve body (also 2010 Fusion, Mercury Mariner and Milan). The bulletin is on NHTSA, but whether it is still current is not verified, so it is labelled vehicle data rather than confirmed.

  • 2013–2016 · F-150

    Supported by vehicle data

    Owners report P0735 with slipping while towing and wrong gear displayed, per complaints to NHTSA. These are owner reports, not a bulletin.

  • ASI-44733Status unverified

    Worn solenoid pressure regulator valve with P0735

    2009–2010escape, fusion · issued · NHTSA 10057860

    Valve body with a worn solenoid pressure regulator valve and P0735 stored. Also Mercury Mariner and Milan; Fusion and Milan are 2010 only. Only the NHTSA flat-file summary was read, not the bulletin itself.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • P0775Pressure control solenoid B malfunction

    Shares causes Possible — needs testing

    A 2002 Explorer owner reported P0775 and P0735 together before a transmission replacement was proposed.

  • P0730Transmission gear ratio does not match the selected gear

    Same system Possible — needs testing

    P0730 is the general incorrect gear ratio code; P0735 is the 5th-gear version.

All Transmission codes

Sources and review

  1. Toyota Camry Owner's Manual (OM06291U) — Toyota
  2. P0735 Gear 5 Incorrect Ratio — TAT Scan Data (Australia)
  3. NHTSA complaint 11180006: 2013 Ford F-150, P0735 — NHTSA Office of Defects Investigation
  4. NHTSA complaint 11550604: 2018 Ram 2500, P0735 — NHTSA Office of Defects Investigation
  5. Cal. Code Regs. Tit. 13, § 1968.2 — Malfunction and Diagnostic System Requirements (OBD II) — California Air Resources Board (via Cornell LII)
  6. Ford ASI-44733: worn solenoid pressure regulator valve with P0735 — Ford Motor Company ,
  7. NHTSA complaint 10317785: 2002 Ford Explorer, P0775 — NHTSA Office of Defects Investigation
  8. Delaware DMV OBD II diagnostic trouble code list — Delaware Division of Motor Vehicles
  9. NHTSA complaint 11725779: 2016 Ford F-150, P0735 — NHTSA Office of Defects Investigation
Last reviewed
Written by
Saurabh K.
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