[Mr. Wyndham]

Because I'm an overachiever, I also found info about the 6L50 Auto...

2007 Hydra-Matic 6L50 (MYB)

2007 Model Year Summary
Hydra-Matic 6L50 six-speed automatic rear- or all-wheel-drive Car & Truck transmission

● All-new Six-Speed Automatic Transmission
● New applications: Cadillac STS, SRX
● Modular Design For Application Flexibility

Full descriptions of new or changed features

ALL-NEW SIX-SPEED AUTOMATIC TRANSMISSION
The new Hydra-Matic 6L50 six-speed automatic transmission is derived from the same modular design as the 6L80, however it uses a slightly smaller aluminum case with gearsets, carriers, input and output shafts and bearings having been optimized for applications that require less torque handling capability than the 6L80. This results in an overall mass reduction and enables a more efficient vehicle.

NEW APPLICATIONS: CADILLAC STS, SRX
The new Hydra-Matic 6L50 transmission debuts in the 2007 Model Year rear-drive and all-wheel-drive Cadillac STS V8 performance sedan, as well as the Cadillac SRX V8 crossover vehicle. The STS and SRX get the six-speed transmission mated to the optional Northstar 4.6L V8 engine.

MODULAR DESIGN FOR APPLICATION FLEXIBILITY
The 6L80 was designed to accept different engines and different mounting locations, as well as the ability to mate to transfer cases for all-wheel-drive capability. It is derived from the similar 6L80 rear- and all-wheel-drive capable six-speed automatic transmission available in the Chevrolet Corvette, the Cadillac XLR, as well as Cadillac and GMC full-size SUVs.

OVERVIEW
The all-new Hydra-Matic 6L50 six-speed automatic transmission for rear- and all-wheel-drive cars is designed with the same modular flexibility as the larger 6L80, as well as being fully compatible with advanced electronic controls. Its unique output gearset configuration enables it to have a wider range of ratios than a conventional planetary gearset automatic transmission.

The main housing for both the STS sedan and the SRX crossover vehicle is identical. The modular concept of the new Hydra-Matic 6L50 centers on the desire for common components and manufacturing tooling for four different size variants of the new 6-speed family. Like the larger 6L80, the 6L50 uses three gearsets, a simple input planetary gearset, and two output gearsets, one of which is a compound gearset with three pairs of two pinion gears on the output carrier, one pair meshing with the sun gear and the other with the ring gear. This arrangement allows for optimal ratio steps with a 6.04:1 overall spread.

All applications feature adaptive shift controls. Several additional features such as grade braking, Performance Algorithm Shifting, and Driver Shift Control are available on some of the applications. Performance Algorithm Shifting (PAS), which detects when the vehicles are being driven in a spirited fashion and remains in its current gear ratio even when the driver lifts a foot off the accelerator pedal. PAS monitors how assertively the driver is using engine output to determine at what engine speed to upshift of downshift. Driver Shift Control, available in the STS and SRX, allows the driver to shift the transmission like a clutchless manual gearbox. Electronic safeguards prevent over-revving should the wrong gear position be accidentally selected.

The wide overall ratio spread of 6.04:1 allows a “steep” first gear, as well as very “tall” overdrive top gear for low-rpm highway cruising. Acceleration is maximized, as is fuel economy. Engine noise is also lower during cruising. Both fifth and sixth gears are “overdrive” gears, for example.

Gear changes from second to sixth gear ratios are accomplished with clutch-to-clutch action, where an “oncoming” clutch is engaged and an “offgoing” clutch is released in a precise manner to achieve the ratio change. The first-to-second upshift, however, is a freewheeling action, where the second gear clutch engages while the first gear one-way clutch spins freely. This allows a greater degree of smoothness at lower vehicle speeds. The manner in which each gear is selected in the 6L50 is optimized for best performance.

Advances in transmission control modules allow the modules to exist reliably inside the transmission, where temperatures remain fairly constant compared to a body-mounted module. The smaller size of the module means the transmission case can be more compact. The transmission and module are assembled together, so no additional steps are necessary during vehicle assembly.

The 32-bit transmission control module (TCM) monitors transmission performance and compensates for normal wear in components such as clutch plates, so transmission performance remains consistent for the life of the transmission. The control module also “tests” the components of the transmission following assembly to optimize the interaction of the components. The module strategy, developed by GM Powertrain, is compatible with future global applications.

The STS and SRX use a 258mm diameter torque converter which features a twin-plate lockup clutch, which also makes use of GM’s proprietary electronic controlled capacity clutch (ECCC) technology. ECCC uses a small, regulated amount of slip to dampen out engine pulses. This creates a smoother running drivetrain, especially during shift events.

The 6L50 all-wheel-drive transfer case in the Cadillac STS application uses an open center differential. The transfer case was upgraded with a heavy-duty drive chain and a larger flange for the output shaft constant velocity joint to handle the greater torque output from the 6L50 first gear. This transfer case is similar but smaller in size than the transfer case used by the 6L80 in the Cadillac Escalade SUVs.

Low maintenance
The 6L50 uses DEXRON® VI premium fluid, which is validated to improve durability and shift stability over the life of the transmission. DEXRON® VI, was developed to have a more consistent viscosity profile; a more consistent shift performance in extreme conditions; and less degradation over time. Internal GM tests have demonstrated DEXRON® VI delivers more than twice the durability and stability in friction tests compared to existing fluids. The DEXRON® VI fluid was designed specifically and validated for the new family of GM six-speed automatic transmissions.

The Hydra-Matic 6L50 is produced in Ypsilanti, Michigan.

Type: six speed RWD / AWD, electronically controlled automatic overdrive transmission with torque converter clutch. Clutch-to-clutch architecture, with integral Electro / Hydraulic Controls Module
Maximum engine power:......315 bhp ( 235 kw )
Maximum engine torque:......332 lb-ft ( 450 Nm )
Maximum gearbox torque:....480 lb-ft ( 651Nm )
Gear ratios:......................MYB
First:...............................4.06
Second:...........................2.37
Third:..............................1.55
Fourth:............................1.16
Fifth:...............................0.85
Sixth:..............................0.67
Reverse:..........................-3.2
Maximum shift speed...........7000 rpm
Maximum Validated Weights: ( Target ) GVW: 6613 lb ( 3000 kg ), GCVW: 12505 lb ( 5672kg )
7-position quadrant: P, R, N, D, X, X, X ( X = available calibratable range position )
Case description: 3-piece ( Bell, main, extension )
Case material: die cast aluminum
Shift pattern: (2) Three-way on/off solenoids
Shift quality: Five variable bleed solenoid
Torque converter clutch: Variable Bleed Solenoid ECCC
Converter size: 258, 280mm ( reference )
Fluid type: DEXRON® VI
Transmission weight: w/258mm converter wet: 85-90 kg ( 187-198 lb ) estimated
Pressure taps available: line pressure

Assembly sites: GMPT Strasbourg, France
GMPT Ypsilanti, MI

Applications: Cadillac STS
Cadillac SRX
Available Control Features: Multiple Shift Patterns ( Selectable or Adaptive ), Driver Shift Control ( Tap Up / Tap Down ), Enhanced Performance Algorithm Shifting ( PAS II ), Next Generation Tow / Haul Mode, Engine Torque Management On All Shifts, Altitude and Temperature Compensation, Adaptive Shift Time, Neutral Idle, Reverse Lockout, Automatic Grade Braking, Additional Features: Oil Life Monitor, OBDII / EOBD, Integral Electro/Hydraulic Controls Module ( Tehcm ), Control Interface Protocol - GMLAN

As the previous quote prickled me, this one tickled me: " The Hydra-Matic 6L50 is produced in Ypsilanti, Michigan."