Knowledge You Need for Servicing 9-Speed Transmissions
New for 2015 is the 948TE (Cherokee)/9HP48 (200) 9-speed automatic transmission. This new transmission is available in the all-new 2015 Chrysler 200 as well as 2014 to current year Jeep® Cherokee and Renegade® models. Depending on the model package, the 9-speed transmission can be used with front-wheel drive, single-speed all-wheel/four-wheel drive and 2-speed four-wheel drive systems.
This transmission provides excellent acceleration with fast, smooth and comfortable gear shifting. Coupled with the 2.4L MultiAir® 2 Tigershark® engine, this 9-speed transmission installed in the new Chrysler 200 can achieve highway fuel economy numbers estimated at 36 miles per gallon.
Major Mechanical Components
Two different valve bodies are used in this transmission. The Chrysler 200 uses a park-by-wire valve body, while the Jeep® brand vehicles use a park-by-cable valve body. These valve bodies are not interchangeable.
The park-by-wire version uses a knob shifter (Figure 1) with no linkage between the shifter and transmission. The park pawl is controlled by the transmission control module (TCM) via two solenoids on the valve body. These solenoids work together to engage/disengage the park pawl.
It should be noted that this valve body does not include a limp-in mode. Major faults cause the transmission to shift into neutral.
The 9-speed Jeep® brand vehicles use a center console-mounted shifter that is connected to the transmission via a cable. This allows the driver to select Park, Reverse, Neutral and Drive. The TCM controls the shifting of the nine forward gears.
Dog clutches are new for the 9-speed transmission and the 948TE/9HP48 are the only FCA US LLC transmissions that use this technology. These clutches replace two of the multi-plate friction plates used in other transmissions. Since dog clutches are like gears, whether fully engaged or disengaged, open clutches induce very little drag and closed clutches do not slip. The compact design allows for more ratios within the transmission case.
Major Electrical Components
The TCM reads information from several sensors in the transmission including the transmission range sensor (TRS), oil pressure sensor, temperature sensor and the input/output shaft speed sensors. The TCM uses this information, operator input and vehicle information from the CAN bus to control the various clutch solenoids.
There are 10 solenoids on the park-by-wire valve body and nine on the park-by-cable valve body. The solenoids receive power from terminals three and six on the TCM. If a fault condition exists, the TCM can turn all power off to the solenoids, as necessary. Both valve bodies use three different types of solenoids — current controlled, voltage controlled and electro mechanical. These solenoids are used to vary hydraulic pressure to the converter clutches, toggle hydraulic pressure to engage/disengage the dog clutches and valve bodies, and as the park-lock solenoid in the park-by-wire transmission.
This all-new 9-speed transmission breakthrough delivers fast and smooth gears with responsive acceleration, as well as fuel economy gains due to optimized engine operation and system efficiency. The unit itself weighs 30 pounds less than a comparable 6-speed transmission. A unique set of four overdrive levels improve efficiency while reducing overall noise, vibration and harshness (NVH).
The most unique feature is the large satin chrome-finished knob located on the center console below the heater and air conditioning controls on the Chrysler 200. This is the Rotary E-Shift. Now, shifting is as easy as changing a radio station. Press and turn the knob instead of moving a traditional shift lever.
Rotating the e-shifter electronically selects the desired mode — P, R, N, D and L on the 2.4L equipped models, as well as a Sport mode (S) on the S model. Both the 3.6L V6 and 2.4L 200S models provide the sport mode with an option to manually shift gears with steering wheel paddle shifters. The sport mode also turns the ride and handling dynamics up a notch. Steering and throttle responses are sharpened and the available automatic all-wheel drive (AWD) is 100 percent connected to deliver power to the front and rear wheels for enhanced sports sedan performance. In addition, the unique sport shift schedule has gear hold capabilities while driving in paddle-shift mode. This provides fast and firm shift engagements that disables the top gear for further responsiveness.
The gear sets are nested inside the transmission for a compact design that saves space. As a result of the use of nested carriers, dog clutches and advanced hydraulic-control architecture, higher gear efficiency has been achieved at all speeds compared to previous transmission designs.
The 948TE/9HP48 automatic transmission is a “sealed for life” design and does not require periodic service. The only time the transmission fluid needs to be checked is when abnormal shifts frequently occur or evidence of a transmission fluid leak is present. The fluid filter is mounted internally and requires that the transmission be removed from the vehicle and disassembled to replace the filter. The fluid filter has a plastic body filled with polyester filter fleece.
When the fluid level is checked in the 948TE9/9HP48 automatic transmission, the distance from the upper lip of the fluid level check port, located on top of the transmission housing above the differential, down to the surface of the fluid, is being measured. The special dipstick tool, 10323A, is required. This dipstick is marked in 5 mm increments. The engine must be running at idle with the transmission in park and the vehicle in a level position.
Use the scan tool to display the transmission fluid temperature. Insert the dipstick into the fluid level check port and allow the handle to rest on the flat surface of the transmission housing around the check port. Remove the dipstick from the check port, keeping the handle above the tip so the level reading remains accurate. The temperature of the fluid and the measurement shown on the dipstick should be compared to graph in the appropriate service manual to determine the proper fluid level.
NOTE: The fluid used in this automatic transmission is not compatible with other types of transmission fluid. Use only Mopar® 8 & 9 Speed ATF+4®, P/N 68157995AB, after repairs have been completed. Use of improper fluid will cause premature failure, poor shift quality and possible leaks.