DESCRIPTION
The 41TE is a four-speed transaxle that is a conventional hydraulic/mechanical assembly with an integral differential, and is controlled with adaptive electronic controls and monitors. (Scheme 114) The hydraulic system of the transaxle consists of the transaxle fluid, fluid passages, hydraulic valves, and various line pressure control components. An input clutch assembly which houses the underdrive, overdrive, and reverse clutches is used. It also utilizes separate holding clutches: 2nd/4th gear and Low/Reverse. The primary mechanical components of the transaxle consist of the following
- Three multiple disc input clutches
- Two multiple disc holding clutches
- Four hydraulic accumulators
- Two planetary gear sets
- Hydraulic oil pump
- Valve body
- Solenoid/Pressure switch assembly
- Integral differential assembly
Scheme 114
Control of the transaxle is accomplished by fully adaptive electronics. Optimum shift scheduling is accomplished through continuous real time sensor feedback information provided to the Transmission Control Module (TCM).
The TCM is the heart of the electronic control system and relies on information from various direct and indirect inputs (sensors, switches, etc.) to determine driver demand and vehicle operating conditions. With this information, the TCM can calculate and perform timely and quality shifts through various output or control devices (solenoid pack, transmission control relay, etc.).
The TCM also performs certain self-diagnostic functions and provides comprehensive information (sensor data, DTC's, etc.) which is helpful in proper diagnosis and repair. This information can be viewed with the DRB scan tool.
The 41TE transaxle identification code is a series of digits printed on a bar code label that is fixed to the transaxle case as shown in (Scheme 115)
Scheme 115
For example, the identification code K 821 1125 1316 can be broken down as follows
- K = Kokomo Transmission Plant
- 821 = Last three digits of the transaxle part number
- 1125 = Build date
- 1316 = Build sequence number
If the tag is not legible or missing, the "PK" number, which is stamped into the transaxle case behind the transfer rear cover, can be referred to for identification. This number differs slightly in that it contains the entire transaxle part number, rather than the last three digits.
OPERATION
Transmission output is directed to an integral differential by a transfer gear system in the following input-to-output ratios
Scheme 116
The 41TE underdrive, overdrive, low/reverse, and 2/4 clutch hydraulic circuits each contain an accumulator. An accumulator typically consists of a piston, seals, return spring(s), and a cover or plug. The overdrive and underdrive accumulators are located within the transaxle case, and are retained by the valve body. (Scheme 117)
Scheme 117
The low reverse accumulator is also located within the transaxle case, but the assembly is retained by a cover and a snap-ring. (Scheme 118)
The 2/4 accumulator is located in the valve body. It is retained by a cover and retaining screws. (Scheme 119)
Scheme 118
Scheme 119
The function of an accumulator is to cushion the application of a frictional clutch element. When pressurized fluid is applied to a clutch circuit, the application force is dampened by fluid collecting in the respective accumulator chamber against the piston and spring(s). The intended result is a smooth, firm clutch application.
Three hydraulically applied input clutches are used to drive planetary components. The underdrive, overdrive, and reverse clutches are considered input clutches and are contained within the input clutch assembly. (Scheme 120) The input clutch assembly also contains
Scheme 120
- Input shaft
- Input hub
- Clutch retainer
- Underdrive piston
- Overdrive/reverse piston
- Overdrive hub
- Underdrive hub
The three input clutches are responsible for driving different components of the planetary geartrain.
Note. Refer to the "Elements In Use" chart see scheme 4 for a collective view of which clutch elements are applied at each position of the selector lever.
The 41TE differential is a conventional open design. It consists of a ring gear and a differential case. The differential case consists of pinion and side gears, and a pinion shaft. The differential case is supported in the transaxle by tapered roller bearings. (Scheme 121)
Scheme 121
The differential assembly is driven by the transfer shaft by way of the differential ring gear. The ring gear drives the differential case, and the case drives the axle shafts through the differential gears. The differential pinion and side gears are supported in the case by thrust washers and a pinion shaft. Differential pinion and side gears make it possible for front tires to rotate at different speeds while cornering.
Two hydraulically applied multi-disc clutches are used to hold planetary geartrain components stationary while the input clutches drive others. The 2/4 and Low/Reverse clutches are considered holding clutches and are contained at the rear of the transaxle case. (Scheme 122)
Scheme 122
Note. Refer to the "Elements In Use" chart in see scheme 4 for a collective view of which clutch elements are applied at each position of the selector lever.
The oil pump is located in the pump housing, inside the bell housing of the transaxle case. (Scheme 123) The oil pump consists of an inner and outer gear, a housing, and a cover that also serves as the reaction shaft support.
Scheme 123
As the torque converter rotates, the converter hub rotates the inner and outer gears. As the gears rotate, the clearance between the gear teeth increases in the crescent area, and creates a suction at the inlet side of the pump. This suction draws fluid through the pump inlet from the oil pan. As the clearance between the gear teeth in the crescent area decreases, it forces pressurized fluid into the pump outlet and to the valve body.
The planetary geartrain is located between the input clutch assembly and the rear of the transaxle case. The planetary geartrain consists of two sun gears, two planetary carriers, two annulus (ring) gears, and one output shaft. (Scheme 124)
Scheme 124
The planetary geartrain utilizes two planetary gear sets that connect the transmission input shaft to the output shaft. Input and holding clutches drive or lock different planetary members to change output ratio or direction.
Scheme 125
- Remove transaxle from vehicle. (Refer to «REMOVAL»(ref-178094-S03387651642005061000000) ).
- Using Tool C-3981-B, remove oil pump seal. (Scheme 125)
Scheme 126
- Using Tool C-4193, install oil pump seal. (Scheme 126)
- Install transaxle to vehicle. (Refer to «INSTALLATION»(ref-178094-S29448276602005061000000) ).
Scheme 127
Scheme 128
Scheme 129
Scheme 130
Scheme 131
Scheme 132
Scheme 133
Scheme 134
Scheme 135
- Disconnect the battery negative cable.
- Loosen set screw and remove knob from shifter handle. (Scheme 127)
- Remove the center console assembly as shown in (Scheme 128)
- Remove shifter bezel. (Scheme 129)
- Disconnect the shifter/ignition interlock cable from the shifter lever and bracket as shown in (Scheme 130) Remove the cable core end from the plastic cam of the shifter mechanism and release cable from shifter bracket
- Remove the steering column lower cover. (Scheme 131)
- Remove the steering column upper and lower shrouds. (Scheme 132)
- Disconnect the Brake Transmission Shift Interlock (BTSI) solenoid connector from the interlock cable. (Scheme 133)
- Rotate the ignition key to the "OFF" or "ON/RUN" position. (Scheme 134)
- Squeeze the interlock cable locking tab. Remove the cable from the interlock housing. (Scheme 135)
- Release cable from retaining clips and remove through opening under steering column.
The Solenoid/Pressure Switch Assembly is external to the transaxle and mounted to the transaxle case. (Scheme 136) The assembly consists of four solenoids that control hydraulic pressure to the LR/CC, 2/4, OD, and UD friction elements. The reverse clutch is controlled by line pressure from the manual valve in the valve body. The solenoids are contained within the Solenoid/Pressure Switch Assembly, and can only be serviced by replacing the assembly.
The solenoid assembly also contains pressure switches that monitor and send hydraulic circuit information to the TCM. Likewise, the pressure switches can only be service by replacing the assembly.
Scheme 136
The Input Speed Sensor is a two-wire magnetic pickup device that generates AC signals as rotation occurs. It is threaded into the transaxle case (Scheme 137), sealed with an "O" ring. (Scheme 138), and is considered a primary input to the Transmission Control Module (TCM).
Scheme 137
Scheme 138
The Input Speed Sensor provides information on how fast the input shaft is rotating. As the teeth of the input clutch hub pass by the sensor coil (Scheme 139), an AC voltage is generated and sent to the TCM. The TCM interprets this information as input shaft RPM.
Scheme 139
The TCM compares the input speed signal with output speed signal to determine the following
- Transmission gear ratio
- Speed ratio error detection
- CVI calculation The TCM also compares the input speed signal and the engine speed signal to determine the following: Torque converter clutch slippage Torque converter element speed ratio
Scheme 140
Scheme 141
- Disconnect battery negative cable.
- Remove air cleaner/throttle body assembly.
- Disconnect input speed sensor connector.
- Unscrew and remove input speed sensor. (Scheme 140)
- Inspect speed sensor "O" ring (Scheme 141) and replace if necessary.
The Output Speed Sensor is a two-wire magnetic pickup device that generates an AC signal as rotation occurs. It is threaded into the transaxle case (Scheme 142), sealed with an "O" ring (Scheme 143), and is considered a primary input to the Transmission Control Module (TCM).
Scheme 142
Scheme 143
The Output Speed Sensor provides information on how fast the output shaft is rotating. As the rear planetary carrier park pawl lugs pass by the sensor coil (Scheme 144), an AC voltage is generated and sent to the TCM. The TCM interprets this information as output shaft RPM.
The TCM compares the input and output speed signals to determine the following
- Transmission gear ratio
- Speed ratio error detection
- CVI calculation
Scheme 144
The transmission control relay is located in the Power Distribution Center (PDC), which is located on the left side of the engine compartment. (Scheme 145)
Scheme 145
The relay is supplied fused B+ voltage, energized by the TCM, and is used to supply power to the solenoid pack when the transmission is in normal operating mode. When the relay is "off", no power is supplied to the solenoid pack and the transmission is in "limp-in" mode. After a controller reset (ignition key turned to the "run" position or after cranking engine), the TCM energizes the relay. Prior to this, the TCM verifies that the contacts are open by checking for no voltage at the switched battery terminals. After this is verified, the voltage at the solenoid pack pressure switches is checked. After the relay is energized, the TCM monitors the terminals to verify that the voltage is greater than 3 volts.
The Transmission Range Sensor (TRS) is mounted to the top of the valve body inside the transaxle and can only be serviced by removing the valve body. The electrical connector extends through the transaxle case. (Scheme 146)
Scheme 146
The Transmission Range Sensor (TRS) has four switch contacts that monitor shift lever position and send the information to the TCM.
The TRS also has an integrated temperature sensor (thermistor) that communicates transaxle temperature to the TCM and PCM. (Scheme 147)
Scheme 147
The Transmission Range Sensor (TRS) communicates shift lever position (SLP) to the TCM as a combination of open and closed switches. (Scheme 146) Each shift lever position has an assigned combination of switch states (open/closed) that the TCM receives from four sense circuits. The TCM interprets this information and determines the appropriate transaxle gear position and shift schedule. (Scheme 148)
Since there are four switches, there are 16 possible combinations of open and closed switches (codes). Seven of these codes are related to gear position and three are recognized as "between gear" codes. This results in six codes which should never occur. These are called "invalid" codes. An invalid code will result in a DTC, and the TCM will then determine the shift lever position based on pressure switch data. This allows reasonably normal transmission operation with a TRS failure.
Scheme 148
The Torque Reduction Link (TRD) is a wire between the PCM and TCM that is used by the TCM to request torque management. Torque management controls or reduces torque output of the engine during certain shift sequences, reducing torque applied to the transaxle clutches.
The torque management signal is basically a 12-volt pull-up supplied by the PCM to the TCM over the torque reduction link (TRD). Torque management is requested when the TCM pulses this signal to ground. The PCM recognizes this request and responds by retarding ignition timing, killing fuel injectors, etc. The PCM sends a confirmation of the request to the TCM via the communication bus. Torque reduction is not noticeable by the driver, and usually lasts for a very short period of time.
If the confirmation signal is not received by the TCM after two sequential request messages, a diagnostic trouble code will be set.
The valve body assembly consists of a cast aluminum valve body, a separator plate, and transfer plate. The valve body contains valves and check balls that control fluid delivery to the torque converter clutch, solenoid/pressure switch assembly, and frictional clutches. The valve body contains the following components. (Scheme 149)
Scheme 149
- Regulator valve
- Solenoid switch valve
- Manual valve
- Converter clutch switch valve
- Converter clutch control valve
- Torque converter regulator valve
- Low/Reverse switch valve
In addition, the valve body also contains the thermal valve, #2, 3 and 4 check balls, the #5 (overdrive) check valve and the 2/4 accumulator assembly. (Refer to DISASSEMBLY ).
Note. Refer to the SCHEMATICS AND DIAGRAMS for a visual aid in determining valve location, operation and design.