The Feds have closed the investigation pertaining to the 2011-12 Ford

Mustang?s 6-speed manual transmission issues.  For those unaware of

the  investigation, the NHTSA opened an investigation back in August

after several 2011-12 Mustang owners reported problems with their 6-

speed manual transmissions including cold shifting issues, sticky

shifts, grinding gears and noise within the trans.  In total the NHTSA

received 364 unique reports from various owners indicating shift

quality issues.

The NHTSA?s official response was ?There is no indication of loss of

motive power or unreasonable safety risk associated with the alleged

defect in the subject vehicles.?

The official report below addresses the issues and what Ford did to

resolve them.

The Office of Defects Investigations (ODI) analyzed complaint data

provided by Ford as well as complaints submitted to ODI from

consumers.

Ford responded to the NHTSA?s investigation by identifying several

factors that may contribute to the shifting issues including a cold

transmission, clutch stay-out at high engine speeds, gear clash or

grinding, and gradual loosening of clutch plate bolts in some early

production vehicles.

The largest percentage of complaints indicated higher than expected

shift efforts in cold ambient temperatures. These complaints were

related to transmission fluid viscosity and the higher shift efforts

resolved themselves with the drivetrain warming. Ford published

technical service bulletin TSB 11-3-18 to inform technicians that a

lower viscosity fluid was available for use to address the cold shift

issues.

The clutch stay-out condition typically occurs at engine speeds

greater than 4000 rpm.  It does not prevent the selection of any gear,

but may delay clutch re-engagement depending on how long the driver

maintains the higher engine speed. Ford identified rotating inertia of

the clutch components as the root cause and replacement clutch pedal

parts were made available under Ford TSB 10-19-4.

A number of reports alleged increasing difficulty selecting gears

along with gear clash or grinding. Grinding or notchy gear shifts may

be caused by gradual loosening of clutch plate fasteners, which is

promoted by certain aggressive shifting. This condition is progressive

in nature and initially results in symptoms related to shift quality/

feel. Clutch plate bolt loosening will not result in inability to

select any gear unless the progressive symptoms are ignored until

complete clutch failure occurs.

ODI?s analysis identified only five complaints alleging an inability

to shift into gear due to loose clutch plate bolts. None of these

resulted in a stall and gear shifting could occur before engine start.

A revised fastener was designed and implemented in production and is

available for service through a special service message. There is no

indication of loss of motive power or unreasonable safety risk

associated with the alleged defect in the subject vehicles. This

preliminary evaluation is closed.

Source: Ford and NHTSA

Patrick