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Transmission choice for the GT350

Automatic or Manual  

36 members have voted

  1. 1. What would you choose, Manual or Auto?

    • 6 Speed Manual
    • 6 Speed Automatic

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The current Mustang GT uses the 5R55 5-speed auto. The 2011MY Mustang GT will use the 6R80 six-speed automatic transmission, manufactured in Livonia(a great read - scroll down for locations), Michigan.


And you have to love the philosophy and benefits an additional gear provides...

Key to the new 6-speed transmissions is increased gear span compared with 4- and 5-speeds. This allows vehicle powertrains to operate at a more optimum level, depending on the particular driving situation.


“For example, a higher first gear delivers more torque when accelerating from a stop while the deeper overdrive gear enables a vehicle’s engine to use less energy at highway cruising speeds, which saves gas,” says Phil Yuhasz, engineering director, Transmission and Driveline Engineering. “In addition, with two more gears, a 6-speed transmission allows the engine to operate at its optimum efficiency, for a greater period of time, further boosting fuel economy.” (Ford Media)


The 6R transmissions do not use valve bodies, they do not have any mechanical valves to control fluid flow. The 4R70/4R75 and 5R55 trans had regular old automatic valve bodies with a couple solenoids used to activate valves, the Ford 6R, ZF 6-speed, and the CVT all use mechatronic assemblies that have the TCM, modules, turbine shaft sensor, temp sensors etc. integrated into the mechatronic assembly with NO mechanical valves.


The new 6R trans are also very different from the older trans in that they don't have any one way clutches. All upshifts and downshifts are contolled electronically.


I'm still looking for the data for the 6R80 relative to its use behind the new 'Coyote' powerplant. As it is currently used in trucks the gear spread provides some interesting numbers...

The Ford 6R80 (4.17, 2.34, 1.52, 1.14, 0.86, 0.69) with a 5500 rpm upshift, 3.73 gear and a 30" tire diameter puts the:

1-2 @ 33 mph and 3200 rpm in 2nd

2-3 @ 57 mph and 3600 rpm in 3rd

3-4 @ 88 mph and 4200 rpm in 4th

4-5 @ 117 mph and 4200 rpm in 5th

5-6 @ 153 mph and 4400 rpm in 6th


We'll have to see what Ford uses ratio wise, as I would assume that the modular truck 6R80 internals will not carry over without change to optimize shift points in its new application. Interesting factoid is that the Coyote is slated to use the 4.6/5.4 bellhousing bolt pattern. Thus an older case may possibly be put to use here, if it'll fit and isn't too heavy.


Things I'm not big on, such as how it is maintained (I'd assume the Mustang 6R80 to be similar, but this is how the trucks are handled)...

Normal maintenance schedule: Transmission fluid change not necessary - Filled For Life

Severe maintenance schedule: Change fluid at 150,000 miles.

Mercon LV is a full synthetic fluid only available from Ford ( LV means Low Viscosity )


I believe Ford started using this unit in ~2007. They've been using them in Explorers/Mountaineers, Expedition/Navigator, and F150 trucks as of late.


Another item of interest...


During production, each transmission built at Livonia will develop a sophisticated “birth history” that allows plant engineers to track every stage of production – starting even before major components arrive at the transmission plant. The system uses sophisticated Radio Frequency Identification (RFID) technology to track components as they move through production – similar to the type of radio frequencies used in a speed pass to pay at gasoline pumps.


Each engine or transmission’s birth history is recorded and maintained in a database related to a bar code. Such data include hundreds of metrics, including torque levels for specific bolts, various testing information and major components identified for traceability.


The birth history allows engineers to trace the precise path taken by any part, so any quality control issue can be traced back to its source, and affected parts taken out of production. “This has potential to save thousands of unnecessary replacements, and spare customers considerable inconvenience,” said Frazier Anderson, plant manager, Livonia Transmission Plant.


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That's what it calls out on the order sheet. Is it a 5 speed?


Tremec lost the contract to Getrag's new 6 speed manual for the 2011 GT.

Tremec, not to be outdone, developed this little beauty - the new T56 Magnum 6 speed manual (with longer tail housing to do away with the much despised remote shifter).

The T56 is due to hit the aftermarket this Summer.





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  • 1 month later...

Starting in 1966 through 1970, the Shelby GT350 (and the later GT500) had an automatic trans option. The 1966 a/t C4 was specially constructed to handle the extra HP. The a/t was most commonly seen in the 1966 GT350 Hertz rentals. And even a few Cobra roadsters came with them.

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