M/T - W6DGA Twin Clutch Transmission Characteristics
No: TSB-08-22-002DATE: June, 2008
MODEL:
2008 Lancer Evolution
2009 Lancer Ralliart
SUBJECT:
CHARACTERISTICS OF W6DGA, TWIN CLUTCH - SPORTRONIC SHIFT TRANSMISSION (TC-SST)
PURPOSE
This Technical Service Bulletin outlines some of the characteristics of the Twin Clutch-Sportronic Shift Transmission (TC-SST) to assist dealer staff in responding accurately to customer inquiries.
AFFECTED VEHICLE(S)
2008-on Lancer Evolution MR w/TC-SST
2009-on Lancer Ralliart w/TC-SST
DETAILS
^ Delay in Engine Shut Off After Turning the Ignition Switch to the OFF Position - There is a delay of 1 - 2 seconds for the engine to shut off after the ignition switch is turned to the OFF position. To allow quicker shifts, two gears are always engaged in this transmission. The delay during engine shut down allows the gears to fully disengage. This provides a smoother start up. If the gears remained engaged, the added resistance could lead to hard starting. As a note, the throttle will respond during this 1-2 second period. The transmission should not be shifted during this period.
^ Throttle Delay at Start Up - If the ambient temperature is very low (approx. -20°C, -4°F), engine speed is restricted to 3,000 rpm for approximately 3 seconds after starting, if the gearshift is in N and the brake pedal is not depressed. This is a normal characteristic. Transmission oil viscosity is very high in very cold temperatures and there is a slight possibility of clutch drag. Because gears are always pre-engaged in N, there is a slight possibility that the vehicle could move if the clutch drags.
^ Delayed Engagement from P - Due to the complex nature of the transmission, customers may experience longer gear engagement than they might initially expect. This is a normal characteristic.
^ Flashing "R" indicator on MID - When shifting into R (reverse position), the customer may notice the R in the MID flashing, indicating an unsuccessful shift. This may be due to gear blocking. The TC-SST is an automated manual transmission and occasional gear blocking is possible. If a customer complains of this condition, advise them to shift to a different gear and then retry reverse.
^ Transmission Gear Noise - As mentioned, 2 gears are always engaged at the same time. This means that the transfer gear is in contact with 2 gears and turning 2 shafts within the transmission. This multiple gear selection creates additional noise heard from the transmission when driving. Because gears are always pre-engaged in N, there is a certain amount of N gear rattle.
^ Harsh Shifting in Sport and Super Sport Modes - When in Sport or Supersport modes, the transmission shifts quicker than in Normal mode, and upshifts occur at higher RPM. This can cause a "shock" when shifts occur. This "shock" has been calibrated to provide a shift feed-back to the driver.
^ ECM Control Unit Enhancements - The control units for the engine and the transmission are individual units. The transmission control module (TCM) is located inside the transmission and communicates continuously with the engine control module (ECM) through the Controller Area Network (CAN). Information regarding engine RPM, throttle opening, and output torque are monitored by the TCM to optimize gear shifts. The TCM looks for specific values from the ECM in order to accomplish precise shifts and under some driving conditions, the TCM commands the ECM. Modifying the engine control module or its software, or adding performance equipment (e.g. camshafts, turbocharger, exhaust), may seriously affect the performance and operation of the the engine and/or transmission.
^ Power Braking (Applying the brake and throttle at the same time) - The gear sets of the TC-SST are like those in a manual transmission, but with hydraulic gear and clutch actuation. It features an automated mode where the gears are shifted automatically under the control of a computer. Power is transferred from the engine through clutches like a manual transmission as opposed to through a torque convertor like an automatic transmission. The clutches in the TC-SST are wet-type and located inside the transmission. When power braking an automatic transmission, the clutches within the transmission are fully engaged and the fluid coupling of the torque convertor allows slippage between the engine and transmission. While this does increase automatic transmission oil temperature, there is no slippage of the clutches themselves. The clutches in the TC-SST function more like a manual transmission clutch. If you power brake, the ECM communicates the increase in engine RPM to the TCM, which begins to apply the clutches. This causes them to slip, leading to elevated transmission oil temperature. If the oil overheats, a warning will appear on the Multi-Information Display (MID). Power braking will shorten the life of the clutches.
The ECM will increase idle speed and restrict engine speed to 3,000 RPM until transmission oil temperature decreases to an acceptable value.
^ Cruise Control - Cruise control will not function in Sport or Super Sport modes.
^ Locating the Transmission Serial Number - The transmission serial number is located on the rear cover of the transmission. Look between the Underhood Battery + Terminal and the Air Bypass Valve to locate the serial number label.
^ Checksheets - Use the sheets shown above to report any TC-SST complaints and to record and report Freeze Frame data. Fax the competed form to Techline.