P0733 on Ford: How to Diagnose & Fix
Gear 4 Incorrect Ratio
2 Ford models · 3 documented issues · 3 critical · $25-$4,500 repair
P0733 on Ford by model: symptoms, diagnosis and fix
The 10R80 10-speed automatic (introduced on the 2017 F-150) is widely reported to shift harshly: jerking, clunking, banging on the 1-2 and 2-3 shifts, hesitation, gear hunting, and occasional limp-mode with a 'Transmission Not in Park' or 'drive mode not available' message. Many trucks also exhibit a torque-converter lockup-clutch shudder felt as a vibration around 30-45 mph. Root causes traced in later TSBs include adaptive-calibration mismatch during break-in, CDF drum bushing migration, and valve-body bore wear/scoring. A class action (O'Connor v. Ford, N.D. Illinois) covers the defect.
Common Symptoms
- Harsh 1-2/2-3 upshifts that jerk or clunk
- Loud bang/clunk when starting the truck
- Hesitation, gear hunting, or slipping
- Vibration/shudder at 30-45 mph (torque-converter lockup)
- Limp mode or 'drive mode not available' message
How to Fix
Start with a Ford PCM/TCM reflash to the latest calibration and an adaptive-learning relearn drive cycle (early TSBs 18-2079/18-2274, later 23-2250 superseded by 24-2046). For shudder, a transmission fluid service with Mercon ULV plus friction modifier helps. Persistent harsh shifts with valve-body bore damage require main control valve body replacement (TSB 22-2428). Severe cases need converter or transmission overhaul.
Sources for this issue (1)
The 4-speed automatics behind the 4.0L - the early A4LD and the later electronically controlled 4R44E/4R55E - are a known weak point, commonly failing in the 120k-mile range, most often losing 4th gear (overdrive). The overdrive planetary is fragile (early units used a weaker pinion design, later updated to a 6-pinion gear), and a failing vacuum modulator on the A4LD can quietly cook the overdrive section. When the overdrive sprag or drum lets go, debris circulates and a full rebuild is required. A closely related driveline failure is the powdered-metal spacer between the crankshaft and flexplate: Ford's sintered spacer is brittle and cracks, causing a rattle, vibration, and eventually hard-start/no-start or driveline separation.
Common Symptoms
- No 4th gear / no overdrive engagement
- Slipping or flaring shifts
- Delayed or harsh engagement
- Rattle at idle in gear (cracked flexplate spacer)
- Burnt-smelling transmission fluid
- Vibration or hard-start/no-start (spacer failure)
How to Fix
Service the fluid and filter on a strict interval and add an auxiliary cooler if towing. Replace a suspect A4LD vacuum modulator early (inexpensive ~$25 external part). Lost overdrive or slipping generally requires a rebuild or replacement transmission with updated overdrive components. When the transmission or flexplate is out, replace the brittle OEM powdered-metal crank-to-flexplate spacer with a billet-steel upgrade (e.g., Sonnax) to prevent recurrence.
Sources for this issue (1)
A very common failure on third- and fourth-generation Explorers with the 5R55W/5R55S automatic is wear in the overdrive and intermediate servo bores inside the transmission case. As the bores wear, hydraulic pressure leaks past the servo pistons, leading to 2-3 flare, 3-5 flare, slipping, harsh engagement, and delayed or missing reverse. This issue is widely documented in owner complaints, transmission repair communities, and Ford service literature addressing shift flare and servo-related repairs.
Common Symptoms
- 2-3 shift flare
- 3-5 shift flare
- delayed reverse engagement
- slipping during acceleration
- harsh shifting
- transmission warning light
- loss of reverse
How to Fix
Diagnosis usually includes confirming flare or slip during the 2-3 or 3-5 shift, checking line pressure, scanning for ratio/performance codes, and inspecting servo operation. A lasting repair typically requires installing oversized servo bore sleeves or a remanufactured valve body/case repair kit; fluid changes alone rarely fix worn bores once symptoms are established. If clutch damage has already occurred, a full rebuild may be necessary.
Sources for this issue (1)
P0733 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 P0733 mean on a Ford?
P0733 stands for "Gear 4 Incorrect Ratio." This code indicates the transmission control module found that the actual gear ratio in 4th gear is outside the acceptable range for that gear. It is detected by comparing transmission input speed against output speed while 4th gear is engaged. A mismatch typically signals the transmission is slipping in 4th gear or that a control/hydraulic fault is preventing proper engagement. On Ford it is documented across 2 models: F-150, Explorer.
What are the most common causes of P0733?
The most common causes of P0733 are: Low or contaminated transmission fluid, Worn 4th-gear clutch packs or bands, Failing shift solenoid for 4th gear, Valve body or line pressure issues, Internal transmission mechanical wear, Restricted transmission filter, Faulty input or output speed sensor. The specific cause varies by vehicle.
How much does it cost to fix P0733 on a Ford?
Published repair estimates on Ford range from $25 to $4,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0733 on a different make?
View P0733 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.