On vehicles equipped with an automatic transmission it is imperative that the converter pilot hub be greased with Motorcraft Multi-Purpose Grease Spray XL-5-A even if grease was not applied from the factory. Also verify that the engine/transmission alignment dowel pins are present as well as the engine crankshaft dowel pin, if equipped, when installing the transmission. Failure to adequately lubricate the converter hub greatly increases the likelihood of the flexplate cracking in the future. Missing dowels may cause a misalignment issue also resulting in a premature failure. Refer to Workshop Manual (WSM), Section 307-01.
full bulletin at NHTSA ↗2010 Ford Flex powertrain problems
severe 10 complaints filed with NHTSA · avg repair $2,500 · see powertrain across all vehicles →
Failure mileage
Complaints
10
Recalls
0
Avg fix
$2,500
1fire
When does it fail?
Of the 10 powertrain complaints filed for the 2010 Ford Flex, here's the actual mileage breakdown — failures cluster heaviest at 75,000-100,000 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
No new NHTSA powertrain complaint has been filed on this vehicle in over 8 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.
FORD: IF THERE IS AN INTERMITTENT LACK OF POWER, SURGE, OR HESITATION WHILE DRIVING THE BRAKES WILL OVERRIDE ACCELERATION.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners describe a cascade of powertrain trouble across transmission, PTU, and engine systems. The transmission exhibits erratic shifting behavior from as early as 10,000 miles—awkward engagement, unexpected downshifts into first gear at highway speed, unresponsiveness to gear selection, and frequent slipping. One owner's transmission lurched from high gear to first on a downhill decline at 45+ mph, nearly causing a rear-end collision; another reported violent jerking that dealers couldn't duplicate.
The Power Transfer Unit (PTU) fails between 72,000 and 87,506 miles with fluid leaks; in one case, leaking fluid ignited when exposed to exhaust heat at 40 mph, causing severe powertrain damage. The original PTU design lacked a drain plug and couldn't be serviced. Replacement cost one owner $1,692.26. Ford issued two TSBs for PTU replacement but no recall.
EcoBoost engines suffer head gasket failure when exhaust pressure redirects to cylinders 3 and 5, allowing coolant into the cylinder head and causing motor destruction by 74,000 miles. One owner calls it "very common" in the 2010 Flex.
Intermittent power loss events occur where the engine cuts out, the wrench light appears, and transmission won't move—resolved only by restarting. One owner also reports unexplained forward lurching while stopped at lights and while coasting at minimal speed.
Dealers made multiple service attempts without fixing any of these issues.
Same Ford Flex powertrain reports on nearby years: 2009 · 2011
Failure modes owners describe
Power Transfer Unit (PTU) Failure and Leaks
PTU fails prematurely, causing transmission fluid leaks and in at least one case, fluid ignition due to exposure to exhaust heat. Original PTU design lacked a drain plug, making service impossible.
When: 72,000–87,506 miles
Symptoms owners cite: Transmission fluid leak detected during routine maintenance; Loud whining noise from PTU starting at 40 mph; Sudden loss of power and transmission unresponsiveness; Severe powertrain failure with transmission housing damage
Repairs/costs cited: PTU replacement cost $1,692.26. Replacement unit includes drain plug. Transmission housing damage also reported in one case requiring repair.
Recalls/TSBs owners mention: Ford issued two TSBs to replace PTU but did not issue a recall.
Transmission Shifting and Control Failures
Transmission exhibits erratic shifting behavior, including unexpected downshifts, unresponsiveness to gear selection, and inability to hold gear position. Issues present from early mileage and persist throughout ownership.
When: Starting at 10,000 miles; recurring through 87,506+ miles
Symptoms owners cite: Awkward, erratic shifting since early mileage; Sudden downshift into first gear while driving 45+ mph on decline, causing rapid deceleration and near-collision; Transmission unresponsiveness when attempting gear selection; Vehicle slipping into neutral unexpectedly; Transmission frequently slips during operation; Violent jerking intermittently; Thunk noise when putting vehicle into reverse
Repairs/costs cited: Dealer unable to diagnose or resolve issue through multiple service visits. No repairs performed in some cases despite four attempts to duplicate failure.
Recalls/TSBs owners mention: Manufacturer aware of at least one failure; mechanic suggested transmission might warrant recall in future.
EcoBoost Engine Head Gasket and Motor Failure
EcoBoost engines experience head gasket failure when exhaust pressure is redirected to cylinders 3 and 5, allowing coolant to enter the cylinder head, causing steam damage to cylinders and eventual motor failure.
When: 74,000 miles; reported as common issue affecting motors up to 100,000 miles
Symptoms owners cite: Total motor failure while driving; Head gasket failure; Water/coolant entering cylinder head; Acceleration and stalling symptoms occurring several times per week
Repairs/costs cited: Motor replacement required. Issue described as very common in 2010 Flex with EcoBoost.
Recalls/TSBs owners mention: Owner calls for recall; notes similarity to known F-150 EcoBoost issues.
Sudden Power Loss and Wrench Light Warning
Vehicle loses power and engine management warning light activates during driving. Power is restored after stopping, turning off vehicle, waiting, and restarting. No diagnostic codes stored.
When: Not specified; occurred three times for reporting owner
Symptoms owners cite: Sudden loss of engine power while driving; Wrench warning light illumination; Transmission unresponsive (vehicle won't move); Issue resolves after vehicle restart
Repairs/costs cited: No codes present after restart. Dangerous condition as vehicle stops unexpectedly in traffic.
Unintended Acceleration and Lurching
Vehicle lurches forward unexpectedly when stopped at traffic light or coasting at very low speed, with no driver input to accelerator.
When: Not specified; occurred at least three times, third incident on March 29, 2013
Symptoms owners cite: Sudden forward lurch while foot on brake at red light; Unintended acceleration while coasting at 2–5 mph; Repeated occurrences (at least two incidents before third occurrence)
Synthesized from 10 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 1 most recent
Vehicle was in motion 45+ MPH or so driven on a decline long winding road. Vehicle shifted into first gear from much higher gear causing rapid deceleration and almost rear end collision, pulled in rest area vehicle would not respond to gear select when stopped and went into neutral. Turned off vehicle and put into park let sit and restarted trans worked noticeable thunk when putting into…
Had powertrain trouble with your 2010 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 2010 Ford Flex?
It's a meaningful issue. 10 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 9 complaints that reported odometer mileage, most powertrain failures cluster between 62,900 and 87,506 miles, with the median around 72,000. A quarter of owners report trouble before 62,900; a quarter make it past 87,506. 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/2010/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.