2021 Ford F-150: transmission slipping

Filed Sep 3, 2026 · Transmission · FL

I am reporting a serious safety-related transmission issue involving my 2021 Ford F-150 equipped with the 10R80 automatic transmission. On multiple occasions during normal driving, the transmission has behaved unpredictably and, at times, dangerously. The transmission has suddenly lost the selected gear, slipped or failed to engage, shifted violently, experienced significant RPM flares, unexpectedly downshifted, and harshly clunked into first and second gear while coming to a stop. These events have occurred under a variety of normal driving conditions, including while accelerating, merging onto a highway, making turns, crossing intersections, traveling at highway speeds, driving in stop-and-go traffic, and coming to a stop at red lights. In several instances, the vehicle did not provide the expected acceleration or propulsion when commanded, creating a potentially dangerous situation because I could not reliably predict how or when the truck would respond to throttle input. Of particular concern is the possibility of losing propulsion or experiencing an unexpected gear change while merging into traffic, crossing an intersection, or traveling at highway speed. The unpredictable nature of the transmission makes it difficult to safely operate the vehicle and creates a significant risk of a collision. I believe these symptoms may be related to the known 10R80 CDF clutch-cylinder/sleeve issue. Ford technical information has identified axial movement of the CDF sleeve as a condition that can affect hydraulic circuits and contribute to abnormal transmission operation. The symptoms I have experienced appear consistent with this type of failure. Because these transmission problems have occurred repeatedly and under multiple driving conditions, I believe this issue should be investigated as a potential motor-vehicle safety defect rather than treated solely as a drivability or comfort concern.

Filed Aug 29, 2026 · Transmission · MT

The CDF drum is going bad cause the transmission to slip and downshift while going at highway speeds. Many many many owners report this and Ford created a new CDF drum for owners to put in. However this costs thousands of dollars to replace when they know the CDF drum is faulty.

Filed Aug 3, 2026 · Transmission · TN

I am reporting a safety-related transmission problem I experienced with my 2021 Ford F-150 equipped with the 10R80 automatic transmission. While driving normally, the transmission suddenly downshifted hard, with a jolt that shook the whole truck, then went into emergency limp mode, where I had to pull over to the shoulder, on Interstate 240 in heavy traffic. I was attempting to accelerate to merge into merging traffic. Because of this it created a dangerous situation because the truck did not respond as expected when I needed predictable acceleration or propulsion. Other times I have had hard shifting, but did not result going into limp mode. I believe this incident may be related to the known 10R80 CDF clutch-cylinder/sleeve problem. Ford technical information identifies axial movement of the CDF sleeve that can cause hydraulic-circuit leaks and harsh or delayed engagement and shifting. This condition can result in slipping, RPM flares, delayed engagement, unexpected gear changes, harsh downshifts, lurching, or loss of propulsion. This is a safety concern, not merely a transmission quality or reliability issue. Unexpected loss of propulsion or unpredictable shifting while merging, accelerating into traffic, crossing an intersection, turning, or traveling at highway speed can create a collision hazard. Because I personally experienced this unexpected transmission event, I request that the federal safety agency investigate the 10R80 CDF clutch-cylinder/sleeve condition in Ford F-150s. Please review Ford warranty claims, dealer repair records, transmission replacements, consumer complaints, and field-failure data to determine whether this is a safety defect requiring a recall. I believe owners should not have to wait for a potentially dangerous transmission failure before this known condition is addressed.

Filed Aug 1, 2026 · Transmission · MA

I am reporting a safety-related transmission failure I experienced with my 2021 Ford F-150 equipped with the 10R80 automatic transmission. While driving normally, the transmission suddenly failed to engage and then shifted violently, causing an unexpected loss of power and then a change of propulsion. This occurred while merging at highway speed, creating a potentially dangerous situation because the truck did not respond as expected when I needed acceleration. I believe this incident may be related to the known 10R80 CDF clutch-cylinder/sleeve problem. Ford technical information for 2021–2022 F-150s identifies axial movement of the CDF sleeve that can cause hydraulic-circuit leaks and harsh or delayed engagement and shifting. This can result in slipping, RPM flares, delayed engagement, unexpected gear changes, harsh downshifts, lurching, or loss of propulsion. This is a safety concern, not merely a transmission quality issue. Unexpected loss of propulsion while merging, accelerating into traffic, crossing an intersection, or turning could leave a driver unable to accelerate as expected and create a collision hazard. An unexpected downshift or lurch can also abruptly alter vehicle behavior. Because I personally experienced this unexpected transmission event, I request that the federal safety agency investigate the 10R80 CDF clutch-cylinder/sleeve condition in 2021 F-150s. Please review Ford warranty claims, dealer repair records, transmission replacements, consumer complaints, and field-failure data to determine whether this is a safety defect requiring a recall. I believe owners should not have to wait for a potentially dangerous transmission failure before this known condition is addressed.

Filed Aug 1, 2026 · Transmission · TX

I am reporting a safety-related transmission problem l experienced with my 2021 Ford F-150 equipped with the 10R80 automatic transmission. While driving normally, the transmission suddenly will shift gears violently, unexpectedly downshifted. This occurred while accelerating, merging onto a highway, turning, crossing an intersection, traveling at highway speed, stop-and-go traffic, creating a potentially dangerous situation because the truck did not respond as expected when I needed predictable acceleration or propulsion. I believe this incident may be related to the known 10R80 CDF clutch-cylinder/sleeve problem. Ford technical information identifies axial movement of the CDF sleeve that can cause hydraulic-circuit leaks and harsh or delayed engagement and shifting. This condition can result in slipping, RPM flares, delayed engagement, unexpected gear changes, harsh downshifts, lurching, or loss of propulsion. This is a safety concern, not merely a transmission quality or reliability issue. Unexpected loss of propulsion or unpredictable shifting while merging, accelerating into traffic, crossing an intersection, turning, or traveling at highway speed can create a collision hazard. Because I personally experienced this unexpected transmission event, I request that the federal safety agency investigate the 10R80 CDF clutch-cylinder/sleeve condition in Ford F-150s. Please review Ford warranty claims, dealer repair records, transmission replacements, consumer complaints, and field-failure data to determine whether this is a safety defect requiring a recall. I believe owners should not have to wait for a potentially dangerous transmission failure before this known condition is addressed.

Filed Aug 1, 2026 · Transmission · NY

I am reporting a safety-related transmission problem I experienced with my 2021 Ford F-150 equipped with the 10R80 automatic transmission. While driving normally, the transmission suddenly downshifts aggressively resulting in the rear tires locking up and sliding for a moment. This occurs while driving in stop and go traffic as well as coming to a stop light/sign, creating a potentially dangerous situation. I believe this incident may be related to the known 10R80 CDF clutch-cylinder/sleeve problem. Ford technical information identifies axial movement of the CDF sleeve that can cause hydraulic-circuit leaks and harsh or delayed engagement and shifting. This condition can result in slipping, RPM flares, delayed engagement, unexpected gear changes, harsh downshifts, lurching, or loss of propulsion. This is a safety concern, not merely a transmission quality or reliability issue. Unexpected loss of propulsion or unpredictable shifting while merging, accelerating into traffic, crossing an intersection, turning, or traveling at highway speed can create a collision hazard. Because I personally experienced this unexpected transmission event, I request that the federal safety agency investigate the 10R80 CDF clutch-cylinder/sleeve condition in Ford F-150s. Please review Ford warranty claims, dealer repair records, transmission replacements, consumer complaints, and field-failure data to determine whether this is a safety defect requiring a recall. I believe owners should not have to wait for a potentially dangerous transmission failure before this known condition is addressed.

Filed Aug 1, 2026 · Transmission · MD

I am reporting a safety-related transmission problem I experienced with my 2021 Ford F-150 equipped with the 10R80 automatic transmission. While driving normally, the transmission suddenly slammed into the next gear, i had never felt that before, it happens when it shifts from 2nd gear to 3rd, and someone’s after i have already been driving at highway speeds for a while it will rev up as if it’s slipping or missing a gear. This occurred while driving on a main highway, and also happens right when i leave my driveway, creating a potentially dangerous situation because the truck did not respond as expected when I needed predictable acceleration or propulsion. A loss of power in the middle of busy traffic could cause an accident. This happens every single time i drive my truck, currently my truck has less than 55k miles. I believe this incident may be related to the known 10R80 CDF clutch-cylinder/sleeve problem. Ford technical information identifies axial movement of the CDF sleeve that can cause hydraulic-circuit leaks and harsh or delayed engagement and shifting. This condition can result in slipping, RPM flares, delayed engagement, unexpected gear changes, harsh downshifts, lurching, or loss of propulsion. This is a safety concern, not merely a transmission quality or reliability issue. Unexpected loss of propulsion or unpredictable shifting while merging, accelerating into traffic, crossing an intersection, turning, or traveling at highway speed can create a collision hazard. Because I personally experienced this unexpected transmission event, I request that the federal safety agency investigate the 10R80 CDF clutch-cylinder/sleeve condition in Ford F-150s. Please review Ford warranty claims, dealer repair records, transmission replacements, consumer complaints, and field-failure data to determine whether this is a safety defect requiring a recall. I believe owners should not have to wait for a potentially dangerous transmission failure before this known condition is addressed.

Filed Aug 1, 2026 · Transmission · TX

I am reporting a safety-related transmission problem I experienced with my 2021 Ford F-150 equipped with the 10R80 automatic transmission. While driving, the transmission would unexpectedly hesitate before engaging the selected gear and then shift harshly with a noticeable bang. On multiple occasions, the engine RPM would flare before the transmission engaged, resulting in delayed or inconsistent acceleration. The transmission has also exhibited harsh shifts, delayed engagement, and unpredictable gear changes. These events occurred during normal driving, including accelerating from a stop, merging into traffic, and driving at highway speeds. The transmission did not respond as expected when I needed predictable acceleration, creating a potentially dangerous situation. Delayed engagement and sudden harsh shifts make it difficult to judge available power when entering traffic or changing lanes. I believe this incident may be related to the known 10R80 CDF clutch-cylinder/sleeve problem. Ford technical information identifies axial movement of the CDF sleeve that can cause hydraulic-circuit leaks, resulting in harsh or delayed engagement and shifting. This condition can cause slipping, RPM flares, delayed engagement, unexpected gear changes, harsh downshifts, lurching, or loss of propulsion. This is a safety concern, not merely a transmission quality or reliability issue. Unexpected hesitation, delayed engagement, or loss of propulsion while merging, accelerating into traffic, crossing an intersection, or traveling at highway speed creates an increased risk of a crash. Because I personally experienced these unexpected transmission events, I request that the federal safety agency investigate the 10R80 CDF clutch-cylinder/sleeve condition in Ford F-150 vehicles. Please review Ford warranty claims, dealer repair records, transmission replacements, consumer complaints, and field-failure data to determine whether this represents a safety defect

Filed Jun 29, 2026 · Transmission · TX

Component/system affected: Power train / automatic transmission. Description of safety issue: The transmission has recurring harsh and erratic shifting, most noticeable on the first drive of the day. Symptoms include slipping/flaring, delayed or failed upshifts, sudden harsh gear engagement, unexpected large gear changes, loss of power, and occasional operation as if stuck in 4th gear/limp mode. The issue has become severe enough that I have had to manually intervene and pull over. Specific safety incident: On or about June 24th, I was leaving my apartment complex and turning left onto a busy main street. As I approached and entered the turn, the truck was in 1st gear and I was pressing the accelerator, but the transmission appeared to struggle or delay shifting into the next gear. The vehicle did not respond normally, so I continued applying throttle to complete the turn. When the transmission finally shifted, it engaged extremely harshly and caused the truck to lurch forward unexpectedly into the intersection. I had to slam on the brakes to narrowly avoid colliding with another vehicle. This created a serious crash risk because the vehicle first had delayed/lost propulsion and then suddenly surged forward during a left turn across traffic. Safety risk: This defect can cause unexpected loss of motive power, delayed acceleration, harsh engagement, and sudden vehicle lurching while driving. This is especially dangerous when merging, turning across traffic, entering intersections, passing, or driving at highway speed. The problem occurs without a clear warning light or check-engine light, so the driver may not have advance warning before the transmission behaves unpredictably. I am reporting this because the 10R80 transmission behavior caused a near crash due to delayed acceleration followed by sudden harsh engagement/lurching into traffic, and because the failure appears consistent with a known valve body/CDF drum issue affecting Ford 10-speed transmissions.

Filed Jun 19, 2026 · Transmission · AL

2021 Ford F-150 Platinum VIN: [XXX] Failure around 95,500 miles Symptoms: Harsh shifting in lower gears Intermittent slipping Progressively worsening over several weeks Dealer diagnosis: Internal transmission issues Concerns consistent with CDF drum, clutch, and planetary component issues Repair: Dealer-performed transmission overhaul Updated CDF drum installed Updated clutch and planetary cylinder Updated valve body separator plate Cost: $6,959.15 INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jun 2, 2026 · Engine, Transmission · VA

2021 Ford F-150 Lariat, 5.0L Coyote V8, purchased new, now 65k miles. Two interrelated safety defects: OIL CONSUMPTION: On 3/21/2026 at 62k miles, I discovered the engine was critically low on oil. Only 3 quarts drained during a full oil change, against a rated 8.8 quart capacity. The engine had been running on one third of required oil. The onboard oil life monitor showed 9% remaining and gave NO low-oil warning, no warning lights, no alerts. No external leak. On 5/22/2026, Koons Ford Woodbridge formally confirmed excessive oil consumption after a documented oil consumption test. Ford TSB 19-2365 acknowledges this exact defect on the 5.0L Coyote for 2018-2020 model years, attributing it to high intake manifold vacuum during deceleration fuel shut-off pulling oil into the combustion chamber. The 2021 engine is mechanically identical. TRANSMISSION: Hard and slipping gear shifts reported to Ford within months of purchase in 2021. Ford issued multiple software updates over the years to mitigate the behavior, most recently late 2025. Fix was temporary; hard/slipping shifts returned. CATASTROPHIC FAILURE: While awaiting Ford HQ authorization on repairs, the vehicle suffered complete drivetrain failure on Friday night. Engine lost power and transmission failed entirely. I was near home and coasted safely off the road. Had this occurred at highway speed during my daily commute, the result could have been catastrophic. Vehicle towed to Koons Ford Woodbridge. SAFETY CONCERN: This is my only vehicle, used for daily highway commuting. The oil consumption defect provides no warning before engine damage. The transmission has degraded despite years of Ford software patches. The vehicle has demonstrated total drivetrain failure capability with no driver warning. Ford Corporate case opened: CXH-07446845-G0J0K0. Filing to document this at the federal level and add to the existing pattern of complaints. Requesting the federal safety agency review whether these defects warrant investigation.

Filed May 13, 2026 · Transmission · VA

My 2021 Ford F-150 with the 10-speed transmission has started shifting very hard and making grinding noises while accelerating. The truck will sometimes hesitate between gears and then slam into gear unexpectedly. I have also experienced sudden hard downshifts while driving at normal speeds. The issue seems to be getting worse over time. The grinding noise and harsh shifting are most noticeable during acceleration, but the transmission also feels rough during normal driving. At times it feels like the transmission is slipping before catching again. This creates a safety concern because the truck can unexpectedly jerk, hesitate, or downshift hard in traffic and at highway speeds. I have seen many similar complaints online involving the Ford 10R80 transmission, including issues related to harsh shifting and internal transmission problems. Ford has also issued technical service bulletins related to this transmission. No warning lights consistently appeared before the issue started. The problem has happened multiple times and can be reproduced during regular driving. The vehicle has not yet been fully repaired or diagnosed at the time of this report. The transmission and vehicle are available for inspection upon request.