P0729 on Lincoln: How to Diagnose & Fix
Gear 6 Incorrect Ratio
1 Lincoln model · 1 documented issue
P0729 on Lincoln by model: symptoms, diagnosis and fix
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; this record intentionally has no buy link.
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)
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 on a Lincoln?
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. On Lincoln it is documented across 1 model: Aviator.
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 on a Lincoln?
Repair costs vary widely with the root cause and Lincoln model; each issue on this page carries its own estimate where one is published.
Looking for P0729 on a different make?
View P0729 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.