2009 Mercury Mariner Transmission & Power Train Problems
NHTSA component category: POWER TRAIN · data through 07/12/2026
Source: U.S. NHTSA complaint data. Complaints are unverified reports from vehicle owners — a complaint is not a confirmed defect.
How power train ranks on this vehicle
Share of the 315 complaints citing each category; one complaint can cite several. Full breakdown on the 2009 Mercury Mariner overview page.
What owners report
“DRIVING ON HIGHWAY WITH SPEED CONTROL ON AT 75 MPH, ALL OF THE SUDDEN VEHICLE RAPIDLY SPED UP TO 95 MPH. THE VEHICLE JUST TOOK…”NHTSA complaint 10573444 — filed 03/19/2014
“MY CAR 2009 MERCURY MARINER PREMIER, HAS BEEN SLIPPING (TACH GOES UP BUT MY SPEED DOES NOT) SINCE I BOUGHT THE CAR 2-3 YEARS AGO…”NHTSA complaint 10568028 — filed 03/09/2014
“WHILE DRIVING, THE VEHICLE STARTED LOSING POWER AND THE WRENCH LIGHT CAME ON; STOPPED AND HAD A HARD TIME CRANKING BUT WAS ABLE TO GO…”NHTSA complaint 10558442 — filed 01/04/2014
Excerpts are shortened and scrubbed of personal details; they are individual, unverified reports.
Power Train complaints by year filed
Frequently asked questions
Does the 2009 Mercury Mariner have transmission & power train problems?
Power Train is the #4 most-reported problem area on the 2009 Mercury Mariner: 41 of 315 complaints on file (13%). Complaints are unverified owner reports, not confirmed defects.
How many complaints does the 2009 Mercury Mariner have in total?
315 complaints were on file with NHTSA as of 07/12/2026. Across all categories, 9 involved a crash, 0 involved a fire, 3 reported injuries, and none reported deaths.
What does NHTSA's power train category include?
NHTSA groups complaints about the transmission (automatic or manual), driveline, axles, transfer case and related parts under a single component category called POWER TRAIN. This page reports that category as NHTSA defines it.
