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2008 Tremec TR6060 (MM6/MZ6) Corvette Transmission

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Source: GM Powertrain

2008 Model Year Summary
Tremec TR6060 six-speed manual car transmission

  • Wider gears increase torque-handling capability
  • Stronger one-piece countershaft now standard on all versions
  • Housing strengthened to minimize flex and improve shifting
  • New synchronizer system reduces shift efforts
  • Integrated pump into front adaptor
  • Double-cone reverse gear synchronizer added for easier reverse selection


The addition of wider gears is made possible through the use of special fine-pitch teeth synchronizers (below), which reduces synchronizer travel and creates extra space. First, second and third gears average a 15 percent increase in width as a result. The wider gears handle more torque.

The larger, stronger single-piece output shaft that had been used in high-performance and high-load applications is now standard on all versions of the TR6060.

The transmission housing is strengthened where the shifter rails are held in place with shorter spans. This reduces the chance that the rails will flex during spirited shifting, which improves the solid feel of each shift.

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Patented fine-pitch teeth on the synchronizers and precisely matched machined teeth on the gear bodies reduce synchronizer travel, and further improve the quality feel of shifting. In addition, the shorter travel of the synchronizers effectively increases the ratio of the shifter itself, lowering shift efforts. The shorter travel of the synchronizers also makes extra space available for the use of stronger, wider gears.

The fluid pump used on the higher-performance Z51 option and Z06 model is now integrated into the front case adaptor of the transmission housing. The re-design of the adaptor allowed it to be made stiffer, reducing flex and increasing durability. The new pump itself also has a significantly increased flow, aiding cooling during high-load conditions.

The synchronizer for reverse gear is changed to a double-cone from a single-cone design, which increases the friction area of the synchronizer and makes reverse gear selection easier.


The 6-speed uses Texaco ATF Type III 1863 fluid and is certified "fill-for-life," requiring no fluid changes. The clutch is activated hydraulically, which automatically compensates for clutch disc wear, eliminating manual adjustments. The Tremec TR6060 six-speed has evolved from a design that aimed to require virtually no maintenance in all but the most severe conditions.


Both the standard Corvette and the high-performance Z06 use the TR6060 designated as MM6, which is validated to 500 lb-ft of torque, while the TR6060 with the Z51 option features higher ratios and is designated as MZ6. It is validated to 428 lb-ft of torque.

Design features include a combination of double-cone and triple-cone synchronizers on all gears. Synchronizers act like clutches to speed up or slow down a gear that is being shifted to. Double-cone synchronizers have two friction surfaces to effect this gear acceleration, and triple-cone synchronizers have three friction surfaces. The greater the friction surface, the easier the transmission is to shift. In addition, double-cone and triple-cone synchronizers are smaller in diameter than a single-cone synchronizer with the same friction area allowing the transmission to remain more compact. Bearings in place of bushings lower the friction of the shift rail movements for the Corvette, making the shifter feel naturally lighter and more direct.

Refinements common to the design of all six-speed Tremec TR6060 transmissions include needle bearings on all forward gearsets and 5th and 6th gear synchronizers located on a countershaft. The countershaft location of the 5th and 6th gear synchronizers allow those gears to be selected without affecting the 1st through 4th gearsets, contributing to ease of shifting.

The sixth-generation Corvette with the Z51 option uses the MZ6 version of the six-speed, with ratios developed for the M12 which was used in the Cadillac CTS-V. These ratios are higher in first, second, and third gears than the MM6, as well as a lower-ratio fifth gear to increase top speed for the Z51 option.

When the high-performance Z06 version of the Corvette was introduced for 2006, a stronger single-piece countershaft replaced the previous two-piece countershaft for the MM6. The output shaft was enlarged to a 32-spline unit, which is more durable than the 27-spline unit used in previous applications. Also in 2006 the 6L80 six-speed automatic transmission was introduced, and the bolt pattern for the rear of the case extension of the manual transmission was changed to match the same bolt pattern as the automatic.

Originally, the Tremec T56 evolved as a higher-torque capacity, six-speed version of the proven M49 five-speed manual transmission, and was introduced in the 1993 Chevrolet Camaro and Pontiac Firebird. It was also added to the 1997 fifth-generation Corvette. For the 2008 model year, it has evolved into the TR6060.

Further applications included high-performance models, such as in mid-2004 the Cadillac CTS-V, which used the LS6 engine mated to the M12 higher-ratio version of the transmission, as well as variants that were used in the Pontiac GTO and Chevrolet SSR models.

2008 Tremec TR6060 MM6)11/1/2007
Type: rear wheel drive, six-speed manual overdrive transmission
Engine range: 6.0L - 7.0L gas
Maximum engine torque: 470 lb-ft ( 637 Nm )
Gear ratios: MM6
First: 2.664
Second: 1.783
Third: 1.302
Fourth: 1.000
Fifth: 0.741
Sixth: 0.502
Reverse: 2.903
Final Drive Ratio: 3.420
Maximum validated gross vehicle weight: 4000 lb ( 1680 kg )
Case material: aluminum
Center distance: 85mm
Fluid type: Texaco ATF Type III 1863
Transmission weight: wet: 54.9 kg (121 lb ) 61.5kg
Fluid capacity (approximate): dry: 3.8L (4.0 qt) 117 oz.
Power take off: no
Applications: Chevrolet Corvette
Chevrolet Corvette Z06

2008 Tremec TR6060 (MZ6)11/1/2007
Type: rear wheel drive, six-speed manual overdrive transmission
Engine range: 6.0L
Maximum engine torque: 425 lb-ft ( 576 Nm )
Gear ratios: MZ6
First: 2.966
Second: 2.066
Third: 1.426
Fourth: 1.000
Fifth: 0.710
Sixth: 0.562
Reverse: 3.276
Final Drive Ratio: 3.420
Maximum validated gross vehicle weight: 4000 lb ( 1680 kg )
Case material: aluminum
Center distance: 85mm
Fluid type: Texaco ATF Type III 1863
Transmission weight: wet: 54.9 kg (121 lb )
Fluid capacity (approximate): dry: 3.8L (4.0 qt) 117 oz.
Power take off: no
Applications: Corvette Z51

2008 Tremec MM6/MZ6 Transmission

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