P0729: How to Diagnose & Fix — Gear 6 Incorrect Ratio
8 vehicles · 6 makes · $150-$6,500 repair
How to diagnose and fix P0729: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Ford Fiesta · 2011–2019
The Ford Fiesta equipped with the DPS6 PowerShift dual-clutch automatic transmission is one of the most complained-about vehicles in recent history. The dry dual-clutch design causes severe shuddering, jerking, hesitation, and complete loss of power during acceleration. The clutch plates overheat and wear prematurely, often before 50,000 miles. The Transmission Control Module (TCM) software frequently fails to adapt properly, causing delayed shifts, harsh engagement, and rollback on hills. Ford faced a class-action lawsuit involving nearly 1.5 million vehicles and a federal settlement was reached.
Common Symptoms
- Violent shuddering or bucking during acceleration from a stop
- Transmission slipping and RPMs flaring without acceleration
- Harsh or jerky shifts between 1st and 2nd gear
- Hesitation or delayed engagement when pressing the gas pedal
- Vehicle rolls backward on hills even with foot on gas
- Grinding or chattering noise from transmission area
- Wrench warning light or transmission malfunction message
How to Fix
Check if your vehicle is covered under Ford's extended warranty or class-action settlement — many Fiestas qualify for free clutch and TCM replacement. If out of warranty, have the clutch assembly and TCM reprogrammed or replaced ($1,500-$3,500). Some owners have had success with multiple TCM reflashes to improve shift quality. As a last resort, some owners have converted to a manual transmission. Avoid the PowerShift entirely when purchasing a used Fiesta — manual transmission models are far more reliable.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Transmission Clutch KitCross-refK70564-01
Fitment confirmed against the ShowMeTheParts catalog for this vehicle's year and engine.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (2)
Ford Explorer · 2020–2023
On some Explorers with the 10R60 ten-speed automatic, engagement into gear or shifts can be harsh or delayed, sometimes with the check-engine light on and transmission codes stored. Ford attributes it to transmission-control software, the solenoid ID strategy and/or sticking valves in the main control valve body. It affects 2020–2023 Ford Explorers equipped with the 10R60 ten-speed automatic that show the symptoms or codes listed in bulletin 23-2352 (the bulletin also covers 2020–2023 Aviator and 2021–2023 Bronco with the 10R60).
Common Symptoms
- Harsh or delayed engagement into gear
- Harsh or delayed shifts
- Check-engine light on with transmission codes stored
How to Fix
Have a Ford dealer confirm the symptom and check for later PCM/TCM software. Bulletin 23-2352 specifies a PCM/TCM software update and adaptive learning drive cycle first. If the condition remains and one of the listed codes is stored, the main control valve body is serviced; without codes, vehicles built on or before 1-Nov-2021 first get a transmission solenoid strategy reprogram, and later builds go to the valve body. Ford notes shifts can feel firmer than normal for several days while the adaptive strategy relearns. Normal warranty rules apply; this is not a recall or a promise of free repair.
Sources for this issue (1)
Lincoln Aviator · 2020–2023
Some 2020-2023 Lincoln Aviators equipped with a 10R60 and built on or before December 23, 2022, or a 10R80 MHT and built on or before August 15, 2022, may have harsh or delayed engagement and/or harsh or delayed shifts. Ford TSB 22-2428 says the condition may involve PCM/TCM software, the transmission solenoid-ID strategy, sticking main-control valves, or axial movement of the CDF clutch-cylinder sleeve. The complaint may occur with or without a malfunction indicator and the bulletin's listed transmission DTCs. The symptom alone does not select a valve body, CDF cylinder, or complete transmission.
Common Symptoms
- Harsh engagement
- Delayed engagement
- Harsh shift
- Delayed shift
- Malfunction indicator with a bulletin-listed transmission DTC
How to Fix
Have a Ford/Lincoln-capable technician confirm the transmission and build date, retrieve PCM/TCM faults, and follow TSB 22-2428 in order. The bulletin begins with available PCM/TCM programming and an adaptive-learning drive cycle, then uses the stored faults and clutch behavior to select an accelerated main-control break-in routine. If the condition remains, the procedure can require main-control overhaul and, only after the bulletin's later tests fail, condition-specific internal transmission repair. Parts and coverage must be selected by VIN and the actual failed step.
Call to confirm they can assess your vehicle and perform the stated work. Search results do not confirm qualification, eligibility or coverage.
Owner tips & cautions
- TipRecord the exact shift or engagement event and ask for the PCM/TCM fault report plus the TSB decision-tree step that failed before approving internal transmission work.
- WarningDo not order a valve body or CDF part from harsh shifting alone; Ford's procedure can resolve the condition through programming, adaptive learning, or clutch cycling before parts are selected.
Sources for this issue (1)
Infiniti G37 · 2009–2013
Ford F-150 · 2017–2023
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P0729 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0729 mean?
P0729 stands for "Gear 6 Incorrect Ratio." P0729 means the transmission control system detected an incorrect gear ratio in 6th gear — the computer compares input shaft speed to output shaft speed and found the resulting ratio doesn't match what 6th gear should produce. This usually indicates the transmission is slipping in that gear, a clutch or band isn't holding, or a hydraulic/solenoid control problem is preventing proper engagement. You may feel slipping, flaring RPM, harsh shifts, or the transmission dropping into limp mode. Low fluid and worn internal components are frequent contributors.
What are the most common causes of P0729?
The most common causes of P0729 are: Low or contaminated transmission fluid, Worn or slipping clutches/bands inside the transmission, Faulty shift solenoid or pressure control solenoid, Valve body wear or sticking valves, Failing torque converter, Internal mechanical wear or damage, Speed sensor fault giving incorrect ratio calculation. The specific cause varies by vehicle.
How much does it cost to fix P0729?
Repair costs for P0729 range from $150 to $6,500, depending on the vehicle and root cause.
Which vehicles are affected by P0729?
Au7o has documented P0729 across 8 vehicle models from 6 manufacturers: Chevrolet, Ford, Infiniti, Lincoln, Nissan, Volkswagen.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.