NHTSA Ends Mustang Manual Transmission Investigation

by Patrick Rall

The NHTSA announced in August that they were launching an investigation into a variety of complaints over the 6-speed MT-82 manual transmission in the 2011/2012 Ford Mustang, with which Ford Motor Company replied that they would cooperate fully. Now, thanks in part to Ford’s response to the investigation, the NHTSA has ended their investigation.

In response to the investigation, Ford had issued their thoughts on the complaints about the 6-speed manual transmission found in the Mustang GT and Mustang Boss 302, addressing each of the major complaints with an explanation and their fix for the problem.

The NHTSA’s job is to protect the public from safety issues in vehicles sold in the US, so when 2011 and 2012 Ford Mustang owners began complaining that the 6-speed manual transmission in their Mustang GT or Boss 302 was shifting incorrectly, the investigation ensued. These complaints included cold shifting problems, clutch plate bolt issues, clutch stayout issues, and incidences of 5th gear making a grinding noise – all of which seem to fall short of being safety issues, but frustrating problems for new Mustang owners.

In their incredibly lengthy PDF issued to the NHTSA, Ford Motor Company addressed each of these issues and they even went so far as to elaborate as to more specific causes for these problems. This includes owners who are modifying and “abusing” their cars (read: racing), the influence of online forums that cause owners to read into things too much, a misunderstanding of the skip-shift feature and “driver effect” – which seems in layman’s terms to be Ford’s way of saying that the problem is due to the way that the driver drives.

Cold Shifting Problems:

Ford Motor Company found that 44% of the complaints about the 6-speed manual transmission in the 2011 and 2012 Mustang GT were related to cold shifting problems. When these transmissions were introduced, they were filled with a higher viscosity transmission lube that thickens in temperatures below 60 degrees, so on very cold days, the thickening of the transmission grease can cause increased effort in shifting. This problem will fade as the internal lubrication of the transmission heats up, but Ford addressed this issue with TSB 11-3-18, which instructed dealerships to replace the high viscosity fluid with a lower viscosity lube that does away with these harder shifts on cold days.

Clutch Plate Bolt Problems:

Some complaints on the Mustang’s 6-speed transmission were based around an increasing effort to shift over the life of the vehicle, along with a grinding noise. Ford found that this was due to the clutch plate bolts loosening over time and Ford began using a revised fastener system on October 19th, 2010.

Clutch Stayout Problems:

Some drivers complained about an issue where the clutch would not reengage at higher RPMs, but when the engine speed dropped below 4,000rpm, the clutch would engage. So this should not be classified as a safety issue. Also, Ford found that there was an issue with the spring rate on the clutch return spring, which the company fixed by going to a revised spring setup.

5th Gear Grinding:

Some of the 2011/2012 Mustang GT and Boss 302 owners complained about a grinding noise when in 5th gear. Ford found that there was a component quality issue with the synchronizers for the 5th gear assembly, which Ford Motor Company rectified with the problematic cars.

Now, based on Ford’s report and the NHTSA looking into 364 reports of shift quality issues, the NHTSA has officially ended their investigation. They believe that Ford has properly addressed the various Mustang problems, which do not pose a safety threat.