P0734 on Ford
Gear 4 Incorrect Ratio
P0734 on Ford vehicles indicates gear 4 incorrect ratio. Au7o has documented this code across 4 Ford models — most commonly on Explorer, F-150, Ranger. This code means the Transmission/Powertrain Control Module detected an incorrect gear ratio in 4th gear. The module continuously compares input shaft speed to output shaft speed; if the ratio in 4th gear doesn't match the expected value, it sets P0734. This usually indicates the transmission is slipping or not fully engaging 4th gear due to a hydraulic, friction, or solenoid problem. Symptoms include slipping, flaring RPM, harsh or missed shifts, and possibly limp mode.
Common Causes of P0734
- •Low or degraded/burnt transmission fluid
- •Slipping clutch packs or worn friction elements in 4th gear
- •Stuck or faulty shift solenoid
- •Valve body / internal hydraulic leak or restriction
- •Worn or failing torque converter
- •Faulty input or output speed sensor
- •Internal mechanical wear (bands, planetary gears)
P0734 on Ford by Model
Ford Explorer(1 issue)
- 10R60 Harsh or Delayed Engagement and Shifting2020-2023
Ford TSB 23-2350 covers some 2020-2023 Explorer vehicles with the 10R60 transmission that exhibit harsh or delayed engagement or shifting, sometimes with the malfunction indicator lamp and listed transmission DTCs. Ford identifies several possible causes, including control-module software, solenoid identification strategy, sticking main-control valves, or axial movement of the CDF clutch-cylinder sleeve.
Ford F-150(1 issue)
- 10R80 Adaptive Calibration Can Cause Harsh or Delayed Shifts2017-2020
Ford TSB 23-2250 covers some 2017-2020 F-150 trucks with the 10R80 automatic transmission. Harsh engagement, harsh or delayed shifts, a malfunction indicator lamp, and listed ratio or shift-solenoid DTCs can result when the adaptive calibration does not adapt correctly to hardware break-in over time.
Ford Ranger(1 issue)
- 10R80 Harsh or Delayed Engagement and Shifting2019-2023
Ford TSBs cover some 2019-2023 Ranger vehicles with harsh or delayed engagement or shifts and specified ratio, solenoid, or clutch-performance codes. Ford identifies hydraulic leakage from axial movement of the CDF clutch-cylinder sleeve as one possible cause; a separate current bulletin covers harsh 3-4 or 4-5 upshifts, harsh 5-3 or 4-3 downshifts, or harsh reverse on some 2022-2023 vehicles from F-clutch plate brinelling.
Ford Transit(1 issue)
- 10R80 Harsh or Delayed Engagement and Shift Bulletin2020-2023
Ford TSB 24-2254 covers certain 2020-2023 Transit vehicles with the 10R80 transmission that may have harsh or delayed engagement, harsh or delayed shifts, and specified ratio, shift-solenoid, or clutch-performance DTCs. Ford identifies possible PCM/TCM software, solenoid strategy, sticking main-control valves, or CDF clutch-cylinder sleeve movement rather than one universal cause.
Looking for P0734 on a different make?
View P0734 across all makes →Frequently Asked Questions
What does P0734 mean on Ford?▼
P0734 stands for "Gear 4 Incorrect Ratio." This code means the Transmission/Powertrain Control Module detected an incorrect gear ratio in 4th gear. The module continuously compares input shaft speed to output shaft speed; if the ratio in 4th gear doesn't match the expected value, it sets P0734. This usually indicates the transmission is slipping or not fully engaging 4th gear due to a hydraulic, friction, or solenoid problem. Symptoms include slipping, flaring RPM, harsh or missed shifts, and possibly limp mode. On Ford specifically, this code is documented across 4 models.
What causes P0734 on Ford vehicles?▼
Common causes on Ford: Low or degraded/burnt transmission fluid, Slipping clutch packs or worn friction elements in 4th gear, Stuck or faulty shift solenoid, Valve body / internal hydraulic leak or restriction, Worn or failing torque converter. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0734 on a Ford?▼
Repair costs vary widely depending on the root cause and specific Ford model.
Which Ford models have P0734 documented?▼
Au7o has documented P0734 on 4 Ford models: Explorer, F-150, Ranger, Transit.