Nine facts that make the new Cadillac XT4’s 9-speed transmission stand out in its class
Cadillac’s new contender in the Middle East’s luxury compact SUV market, the all-new XT4 is already impressing customers with its expressive design, roomy interior and advanced technologies. But its extremely confident on-the-road performance, which comes courtesy of a cutting-edge 9-speed automatic gearbox, is also turning heads.
The brand’s first-ever compact SUV is also the first model from Cadillac’s vehicle portfolio to be equipped with GM’s innovative Hydra-Matic 9-speed automatic transmission, ensuring that Middle East owners can enjoy the very best in new vehicle technology on the market.
Paired with the XT4’s 2.0L Turbo engine, the 9-speed automatic gearbox offers an optimal balance of fuel efficiency, performance and refinement. This is helped by the incorporation of a series of hi-tech features that include stop/start technology and the next generation of Electronic Precision Shift, which features an intuitive shifting sequence,
Here are nine facts that make the all-new Cadillac XT4’s 9-speed transmission the perfect gearbox for the compact SUV:
The all-New XT4’s gearbox incorporates the latest stop/start technology. By shutting down the engine in certain stop-and-go driving conditions, this feature contributes to improved fuel efficiency.
A unique accumulator within the transmission stores energy for almost imperceptible engine restarts, while the transmission software calibrated for those restarts further contributes to smooth takeoffs, without any impact on driving refinement.
The transmission’s quick shifts help the XT4’s 237 hp 2-liter turbo engine provide a more immediate feeling of performance - the perfect gear is available whenever the engine’s power reserve is tipped into. Millions of control instructions can be performed every second, ensuring world-class shift time quickness and responsiveness.
As well as being quick, the 9-speed gearbox delivers impressively precise and smooth shifts. A specific strategy is used in the selection of the gearsets, clutches and torque converter.
A space-saving combination of five planetary gearsets, four stationary clutches and three rotating clutches are used. For smoothness, the clutch is engaged in one gear at exactly the same time it is released from another, while a freewheeling shift in first-to-second upshifts contributes to greater refinement at lower vehicle speeds.
This automatic transmission also employs new torque converter technology to deliver smooth take-offs and additional refinement. The thickness of the converter is minimized, keeping the overall width of the engine and transmission as narrow as possible for packaging advantages.
The XT4’s Hydra-Matic 9-speed transmission is far more fuel efficient than 8-speed equivalents, allowing it to return an estimated 7.8 l/100km in highway driving.
The wider overall ratio enables a lower numerical top gear ratio, which contributes to the reassuring fuel efficiency. This is further aided by the fact that the 9-speed automatic has lower friction.
The gearbox offers optimized acceleration and fuel economy and reduced engine noise during cruising thanks to its wider 7.6:1 overall ratio. The difference between the first gear and top gear ratios supports excellent off-the-line acceleration, while the ‘tall’ top gear allows low-rpm highway cruising as well has helping the XT4 to achieve the best efficiency-to-horsepower quotient in its class.
For enhanced braking when travelling downhill, the shift controls include automatic grade braking. A lower gear is selected to help maintain desired vehicle speed when coasting or braking on a downgrade, taking advantage of engine braking. A control module monitors brake pedal usage, vehicle acceleration, throttle position, grade and whether a trailer is connected.
The XT4’s transmission has an on-axis design, where all the gears are in line with the crankshaft, and Cadillac’s first application of a selectable one-way clutch. Both features help reduce the package size, making it roughly the same size as a six-speed transmission.
This is thanks to the elimination of the need for an additional clutch pack - the selectable one-way clutch can hold torque or freewheel, depending on the desired operating mode.
The pressure and volume of the transmission’s hydraulic system are controlled electronically for optimal efficiency. The valve body side cover acts as an internal expansion tank, holding the excess oil until it is required and then returning it to the sump when needed.
It is also filled with a special fluid that does not require changing under normal conditions and offers a more consistent viscosity profile and shift performance in extreme conditions. while degrading less over time.
The all-new XT4’s 9-speed transmission control logic is managed by a transmission control module (TCM), which commands all shifting events to provide smooth and precise ratio changes. The TCM also monitors transmission performance and compensates for normal wear in components such as clutch plates so that performance remains consistent. The TCM also enables manual shift control.