Transmission · Powertrain · generic (SAE-defined)
P0735: Gear 5 Incorrect Ratio
P0735 means the transmission computer found that fifth gear is not producing the expected input-to-output speed ratio, indicating slipping in fifth or a speed signal problem.
Standard title per SAE J2012 / ISO 15031-6 · Updated 2026-11-07 · By CarWhere Research
How P0735 sets
When fifth gear is commanded, the transmission control module (TCM) compares the measured ratio of input to output shaft speed with the fifth-gear ratio. A mismatch beyond the allowed tolerance for a set time sets P0735. Tolerance and timing are manufacturer-specific.
Common causes of P0735
Roughly most likely first; the actual cause depends on the vehicle and needs testing to confirm.
- Low or degraded transmission fluid
- Worn clutches applied in fifth gear
- Faulty shift or pressure control solenoid
- Valve body wear or sticking valves
- Internal seal leakage
- Faulty speed sensor data
P0735 symptoms
- Check engine light on
- Engine speed flare at highway speed
- Transmission will not shift into fifth
- Shuddering or harsh 4-5 shift
- Limp mode on some vehicles
How P0735 is diagnosed
- Read all transmission codes and record freeze frame data
- Check fluid level and condition
- Road test while monitoring input, output and engine speeds in fifth
- Verify speed sensor accuracy
- Check solenoid commands and response
- Perform pressure testing or internal inspection if needed
Typical fixes for P0735
- Correct fluid level or service fluid and filter
- Replace faulty solenoids
- Repair or replace the valve body
- Replace a faulty speed sensor
- Rebuild or replace the transmission if internal clutches are worn
Replace parts only after testing confirms the cause — a code names the circuit or condition that failed a check, not necessarily the faulty part. We don’t publish per-repair prices; for what households actually spend on upkeep, see car repair costs.
Related codes & warning lights
P0735 FAQ
What does code P0735 mean?
P0735 means the transmission computer found that fifth gear is not producing the expected input-to-output speed ratio, indicating slipping in fifth or a speed signal problem. The standard definition is "Gear 5 Incorrect Ratio."
Can I drive with a P0735 code?
Minimize driving, especially at highway speed. Slipping in fifth gear occurs under sustained cruising loads, and the resulting heat can damage clutches and fluid.
Why does P0735 show up mostly on the highway?
Fifth gear is typically engaged at cruising speeds, so any slipping there appears during highway driving rather than around town.
Can using the wrong fluid cause P0735?
Using fluid that does not meet the manufacturer's specification can change clutch friction behavior and contribute to slipping and ratio codes.
Keep researching
More transmission codes
Sources
- SAE J2012 — Diagnostic Trouble Code Definitions (standard code titles)
- ISO 15031-6 — Road vehicles: communication between vehicle and external equipment for emissions-related diagnostics, Part 6: Diagnostic trouble code definitions
- U.S. EPA — Vehicle Emissions Inspection and Maintenance (I/M) programs
- U.S. EPA, 40 CFR 86.1806-17 — Federal onboard diagnostics requirements for light-duty vehicles
General information written by CarWhere Research, not a diagnosis of your vehicle. Manufacturers can add their own sub-definitions and test conditions; confirm with the factory service information for your year, make and model. Before paying for a repair, check NHTSA for open recalls and your warranty booklet: federal law requires an emissions warranty on major emission-control parts such as the catalytic converter and engine computer.