FORD: IF THERE IS AN INTERMITTENT LACK OF POWER, SURGE, OR HESITATION WHILE DRIVING THE BRAKES WILL OVERRIDE ACCELERATION.
full bulletin at NHTSA ↗2009 Ford Flex powertrain problems
severe 19 complaints filed with NHTSA · avg repair $2,500 · see powertrain across all vehicles →
Failure mileage
Complaints
19
Recalls
0
Avg fix
$2,500
1crash
When does it fail?
Of the 19 powertrain complaints filed for the 2009 Ford Flex, here's the actual mileage breakdown — failures cluster heaviest at 150,000+ mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
Of the 8 model years of Ford Flex we track for powertrain problems, this one carries the most owner complaints on file — 19.
No new NHTSA powertrain complaint has been filed on this vehicle in over 6 years — the issue may be aging out of the active population.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering powertrain on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
The 2009 Flex's powertrain issues cluster around transmission dysfunction and unexplained power loss. Cold-start transmission lag in temperatures below 40°F causes the engine to rev to 4000 RPM while the vehicle crawls forward, taking hundreds of feet to hit 25 MPH. Several owners report the "wrench light" problem: the engine loses power, the transmission refuses to accelerate normally, and a yellow wrench light appears—but when you restart the vehicle, the codes vanish and no diagnostic record remains. One owner experienced this 12 times since September 2020, including at 70 MPH on the freeway, forcing emergency lane changes.
Transmission engage failures happen at traffic lights and intersections where the vehicle won't shift out of park or shifts with violent clunking. Some owners describe stalling mid-drive, with the engine refusing to accelerate after restart until it finally kicks in after several minutes. Owners also report grinding noises when shifting, excessive heat in traffic, and a PTU (power transfer unit) seal failure requiring a $2,600 replacement with metal contamination inside. Dealers typically cannot replicate these issues in the shop; many blamed cold conditions, warm conditions, or told owners they could not reproduce the fault under normal service conditions. TSBs exist for some of these symptoms, but Ford has issued no safety recalls.
Same Ford Flex powertrain reports on nearby years: 2010 · 2011
Failure modes owners describe
Cold-start transmission lag and slow acceleration
In cold ambient temperatures (40°F or below), transmission hesitates or slips when shifting into drive after reverse, causing engine to rev to 4000 RPM with very slow vehicle acceleration. Takes 600–1000 feet to reach 25 MPH before shifting into correct gear.
When: Below 40°F ambient temperature, in morning after overnight parking
Symptoms owners cite: Engine revs to 4000 RPM with minimal vehicle acceleration; Extremely slow pickup of speed (600–1000 feet to reach 25 MPH); Delayed gear engagement after shifting into drive
Repairs/costs cited: AAMCO replaced unspecified parts; problem persisted. Transmission fluid level reportedly normal.
Recalls/TSBs owners mention: Ford dealer tested and found no problems; declined to replicate at customer location. Excuses cited: car warmed up or conditions cannot be reproduced.
Unexpected loss of power with wrench light and no stored codes
Vehicle loses power while driving, yellow wrench light illuminates, and engine will not accelerate. Codes clear after restart and the light turns off, leaving no diagnostic record. Occurs unpredictably on freeways and city streets. Happened at least 12 times between September 2020 and report date. Dealership cannot diagnose because codes are erased after restart.
When: Unpredictable; reported 12+ times since September 2020, including at 70 MPH freeway speeds
Symptoms owners cite: Complete loss of engine power while driving; Yellow wrench light illuminates; Vehicle cannot accelerate; Light and codes disappear after restart; Requires engine off/restart to recover; Safety hazard: occurred at 70 MPH requiring emergency lane changes
Repairs/costs cited: No repairs performed; dealership unable to diagnose due to code erasure upon restart.
Recalls/TSBs owners mention: Dealerships cannot identify root cause. Owner mentions forums discuss throttle body, OSS and TSS sensors, but consensus online is throttle body is not the issue.
Engine stalling at low speeds with power steering and brake loss
Engine dies without warning while driving at 28 MPH on residential streets. When engine stalls, power steering locks up and power brakes fail, creating dangerous loss of control. Occurred three separate times (July 2009, August 2009, September 2009) within first few months of ownership. Dealership replaced throttle body after third incident; no stalling reported in week following repair.
When: First year of ownership: July, August, September 2009; at 28 MPH speeds
Symptoms owners cite: Engine shuts off without warning at 28 MPH; Power steering tightens/locks; Power brakes fail; Vehicle coasts to stop
Repairs/costs cited: Ford dealer replaced throttle body after third incident; no stalling reported within one week of repair, though owner noted it was too early to confirm permanent fix.
Recalls/TSBs owners mention: Initial two visits found no codes; third visit led to throttle body replacement.
Wrench light with transmission sluggishness and unintended acceleration
Yellow wrench light appears while driving; when it does, transmission will not accelerate normally until reaching 2nd or 3rd gear. In one instance, after gas pedal was released, vehicle continued accelerating unintentionally, revving to 6000 RPM with foot completely off pedal and no floor mat obstruction. Problem clears after restart; no codes stored.
When: Occurs intermittently; one documented instance around 90,000 miles
Symptoms owners cite: Yellow wrench light illuminates; Transmission sluggish, poor acceleration until 2–3rd gear engagement; Unintended acceleration to 6000 RPM with no pedal input; Symptoms resolve after engine restart
Repairs/costs cited: No repair performed; no codes retrieved at 90,000 miles despite wrench light history.
Transmission will not engage into drive; stuck in park
When stopped at traffic lights or leaving parking spaces, transmission will not engage or shifts very slowly into drive. Vehicle remains stuck and will not move. Requires putting vehicle in park and retrying; sometimes shifts with loud clunk and jerk. Occurs intermittently. Owner notes same issue reported by other 2009 Flex owners and possibly 2015 Transit van owners. Problem more frequent when vehicle is warmed up.
When: Intermittent; worse when transmission is warmed up; reported February 2019 as recent instance
Symptoms owners cite: Transmission stuck, will not engage into drive; Loud clunk or jerk when it finally engages; Vehicle will not move when needed; Repeats intermittently
Repairs/costs cited: Ford dealer unable to replicate in shop; no repairs performed.
Recalls/TSBs owners mention: Dealer claims unable to determine problem if it does not occur during service. Owner reports mechanic found online documentation of this transmission engagement issue on other 2009 Flex units (notably February 21, 2019).
Violent jerking from reverse to park; transmission grinding and overheating
Hard jerk and bang when shifting from reverse to park, frequent but not constant. Vehicle runs hot when sitting in drive-thru or traffic, cools when moving. After independent mechanic replaced fan for cooling issue, grinding noise became severe at idle and while driving—so bad owner was reluctant to drive. Ford dealership found nothing initially, then on follow-up called to say transmission was failing. Vehicle would accelerate on its own, shut off intermittently, and lag between 3rd and 4th gears. Dealership advised transmission replacement. Only whining noise at low speeds after repair.
When: Not specified; another complaint involving $13,000 front-end accident damage and airbag non-deployment at 35 MPH
Symptoms owners cite: Hard jerk and bang from reverse to park; Vehicle overheats when stopped in traffic/drive-thru; Grinding noise at idle and while driving; Vehicle accelerates on its own; Intermittent stalling; Lag between 3rd and 4th gear shifts; Whining noise at low speeds (post-repair)
Repairs/costs cited: Fan replaced by independent mechanic; Ford dealership advised transmission replacement. Whining noise persists at low speeds after repair.
Gas pedal does not slow down when released; poor pedal return design
When driving at steady speed and releasing gas pedal, vehicle does not decelerate as expected. Occurred twice in three borrowed trips with one witness present. Owner attributes issue to poor pedal orientation and light return pressure—foot pressure needs to be completely removed from pedal floor to achieve deceleration. Owner states Ford is aware but claims issue only occurs with heavy work boots; however, owner's incidents occurred in running shoes, size 10.
When: Not specified; borrowed vehicle incidents
Symptoms owners cite: Vehicle does not slow down when gas pedal pressure is merely released; Requires complete foot removal from pedal area to decelerate; Poor pedal return pressure
Recalls/TSBs owners mention: Ford reportedly aware of issue; claims problem only occurs with heavy work boots (owner disputes this).
Transmission stalling while driving with delayed restart engagement
Vehicle stalls while driving without warning. After stopping and restarting, hesitates briefly then kicks into gear and drives normally. Does not happen daily but unpredictability creates safety concern. Owner references TSB 11-12-10 which describes this exact problem. Ford dealerships have no safety recalls for this issue.
When: Intermittent; no specific mileage given
Symptoms owners cite: Stalls while driving; Hesitation and delayed engagement after restart; Unpredictable recurrence
Repairs/costs cited: No repairs performed; no shop diagnosis obtained.
Recalls/TSBs owners mention: TSB 11-12-10 describes the problem, but Ford has no safety recall issued for this defect.
Complete electrical power loss while driving
While driving on freeway at 67°F after 40 minutes of operation, entire dashboard went dark except clock. Power steering and electrical systems shut off. Owner managed to pull vehicle hard to the right (without power steering assist) to shoulder. After turning key off, waiting 3 minutes, and restarting, power returned and has not recurred.
When: Single incident at 1:39 PM, 67°F ambient, after 40 minutes of driving
Symptoms owners cite: Dashboard goes completely dark except clock; Power steering lost; All electrical power except clock lost; Resolved after key-off rest and restart
Engine stumble, power loss, and unresponsive throttle at idle
Engine stumbles and loses power while driving. After restart, idles at 750 RPM and will not respond to accelerator input. Placing car in neutral and pressing accelerator does not increase engine speed. Condition persists 3–4 minutes before engine responds normally to throttle and vehicle accelerates as expected. Occurred three times in past year.
When: Intermittent; three incidents in past year
Symptoms owners cite: Engine stumble; Power loss; Low idle (750 RPM) after restart; Throttle unresponsive for 3–4 minutes; Eventual recovery to normal operation
Lockup and grinding while turning; transmission lag between gears
While making left or right turn, vehicle locks up (transmission engages with hard grinding noise) and slows dramatically. Occurred three times on road, each time causing traffic to stop behind locked-up vehicle. Another complaint mentions grinding noise when turning right initially, then both directions; vehicle shakes when accelerating.
When: Not specified; three road incidents; another complaint notes grinding starting when turning right then progressing to both turns
Symptoms owners cite: Transmission locks up while turning; Grinding noise during lockup; Vehicle slows dramatically; Shaking when accelerating; Grinding extends to turning either direction
Power transfer unit (PTU) seal failure with metal contamination
Power transfer unit seal leaks; in this case, unit contained metal shavings indicating internal wear and required full replacement. Repair cost $2,600. PTU failures reported across multiple Ford models.
When: Not specified; mileage unknown
Symptoms owners cite: PTU seal leak; Metal shavings in PTU fluid indicating internal damage
Repairs/costs cited: Power transfer unit replaced; cost $2,600.
Transmission slipping with safety risk
Transmission slips while driving, nearly causing accident. Specific details sparse in this brief narrative.
When: Not specified
Symptoms owners cite: Transmission slipping; Safety hazard near accident
Transmission shift hesitation between 50–60 MPH ("stuttering")
Vehicle hesitates or stutters while driving 50–60 MPH, as though transmission cannot determine correct gear. Improved after transmission flush and refill (April 2016), but problem persisted. Adding dr. shutter additive to transmission fluid (June 2016) resolved issue.
When: Started 2 years before report date (approximately 2014); fluid service April 2016; additive applied June 2016; problem resolved
Symptoms owners cite: Transmission stuttering/hesitation at 50–60 MPH; Uncertainty in gear selection; Improved but not eliminated by fluid flush/refill
Repairs/costs cited: Transmission flush and refill (April 2016). Addition of dr. shutter additive to transmission fluid (June 2016) resolved issue.
Front axle damage, rear brake caliper bolt detachment, torque converter and transmission seal leaks
At 35 MPH, front of vehicle began vibrating. Diagnosis revealed front axle indentation, rear brake caliper bolts detached, torque converter and transmission seal leaking oil. Technician stated drive line and torque converter required replacement. Vehicle was not repaired.
When: At 101,946 miles
Symptoms owners cite: Front-end vibration at 35 MPH; Rear brake caliper bolts detached; Oil leaks from torque converter and transmission seal
Repairs/costs cited: Front axle replacement needed, rear brake caliper replacement needed, drive line and torque converter replacement needed. Vehicle not repaired.
Recalls/TSBs owners mention: Manufacturer not notified.
Anti-lock brake warning light and vehicle won't start; secure lock system issue
Anti-lock brake warning light illuminated while key was in ignition, preventing vehicle start. Independent mechanic could not determine cause. Dealer stated secure lock system needed reprogramming but was not contacted. Problem recurred. Manufacturer was aware but transferred contact to NHTSA.
When: At approximately 169,000 miles; failure recurred
Symptoms owners cite: Anti-lock brake warning light illuminates; Vehicle will not start; Problem recurs
Repairs/costs cited: Secure lock system reprogramming needed per dealer (not performed).
Recalls/TSBs owners mention: Dealer indicated secure lock system reprogramming needed. Manufacturer transferred complaint to NHTSA.
Synthesized from 19 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 1 most recent
Tl* the contact owns a 2009 Ford flex. While the key was in the ignition, the anti-lock warning indicator illuminated. The contact was unable to start the vehicle. The vehicle was towed to an independent mechanic to be diagnosed, but the cause of the failure was not determined. The dealer stated that the secure lock system needed to be reprogrammed by the dealer. The dealer was not contacted.…
Had powertrain trouble with your 2009 Ford Flex?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the powertrain problem on the 2009 Ford Flex?
It's a meaningful issue. 19 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $2,500.
At what mileage does the powertrain typically fail?
Across the 14 complaints that reported odometer mileage, most powertrain failures cluster between 75,000 and 101,946 miles, with the median around 80,000. A quarter of owners report trouble before 75,000; a quarter make it past 101,946. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
What does it cost to fix?
Independent shops typically charge around $2,500 for powertrain repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to powertrain?
No active recalls currently cover powertrain issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2009/Ford/Flex.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.