![]() When the secondary clutch applies, it delivers torque through the inner shaft to the outer shaft and drives the 1st /3rd and 5th /7th synchronizer hubs. Torque transfers through the mainshaft fixed gear, through the idler gear, and then to the secondary shaft fixed gear, which is part of the secondary inner shaft. ![]() In the example (figure 6), first and second gears are engaged. This allows for very quick and controlled shifts. During the shift, one clutch engages and the other clutch releases. Like a traditional DCT, the Acura DCT engages one clutch at a time, which allows the transmission controller to pre-engage the next gear, whether it’s for an upshift or a downshift. When the clutch applies, it locks the inner and outer shafts together. Just like the mainshaft, the synchronizing assemblies lock the gears to the outer secondary shaft. The outer secondary shaft contains the synchronizing assemblies, which can lock the 1st, 3rd, 5th, and 7th gears to the outer secondary shaft. ![]() The inner secondary shaft drives the secondary clutch housing, and the secondary clutch hub drives the secondary outer shaft. Torque to the secondary shaft (figure 5) comes from a fixed gear on the mainshaft, through an idler gear, and then to a fixed gear on the inner secondary shaft. The synchronizing assemblies use traditional brass synchronizing rings, just like a Honda manual transmission. Since hydraulic servos move the shift rails and engage the desired gear before the clutch applies, the module only needs to control mainshaft and secondary shaft clutch apply and release. When the mainshaft clutch applies, it locks the inner and outer shafts together. The outer mainshaft contains the synchronizing assemblies, which can lock the 2nd, 4th, 6th, and 8th gears to the outer mainshaft. The clutch hub of the mainshaft clutch assembly drives the outer mainshaft. Regarding the mainshaft (figure 4), torque travels from the torque converter turbine through the inner mainshaft and drives the mainshaft clutch assembly. The DCT8 attempts to improve upon the traditional DCT design by using a torque converter to provide smoother operation during vehicle launch and low speeds, but then apply the torque converter clutch once the vehicle reaches the proper speed. When applied, the clutches lock the inner and outer shaft assemblies together. Both the mainshaft and secondary shaft consist of an inner and outer shaft assembly. The dual clutches sit at the end of the mainshaft and the secondary shaft (figure 3). The Acura DCT8 uses a conventional torque converter with a torque converter clutch. Honda addresses these issues with a design modification that provides the smoothness of a traditional automatic with the efficiency of a DCT. Common complaints regarding the traditional DCT involve the quality of low-speed engagements, harshness, and shudder. The traditional DCT is either a wet or dry clutch design. On a traditional DCT, the dual clutches sit in the bellhousing area and are actuated hydraulically (figure 2). The Acura DCT8 presents a different approach to the form and function of the dual clutch, as opposed to a conventional DCT. The addition of hydraulics and electronics allows for automatic shifting. ![]() The DCT contains shift rails and synchronizing assemblies, just like a typical manual transmission. The DCT offers a light and compact design, primarily because it’s more like a manual transmission than a conventional automatic transmission. Let’s take a look at this 8-speed DCT (figure 1).ĭCTs are becoming more popular in performance and fuel-efficient vehicles. Rounding off the Acura lineup is a 7-speed DCT that only shows up in the Acura RLX Hybrid, and the 8-speed dual clutch transmission (DCT), which appears in the popular Acura TLX and ILX. Their latest development is an in-house designed-and-built 10-speed, which appears in their 2018 Honda Odyssey. Over the past few years, Honda has used the ZF 9-speed transmission in the Honda Pilot and Acura MDX. For 2018, Honda will only use torque converter equipped CVTs in the 4-cylinder Accord, Civic, CR-V, Fit, and HR-V. In recent years, you’ll find the start clutch and torque converter equipped CVTs in many of their models. So what does the future hold for Honda transmissions? For 2018, there are no more 5-speed transmissions, but the 6-speed still shows up in certain Honda Odyssey, Ridgeline, Acura RDX, and RLX models. This is how we’ve come to know Honda and Acura transmissions and, along with the many aftermarket enhancements, the Honda 3-shaft, 5-speed is a good moneymaker. The most familiar transmissions are the 5- and 6-speed units, with constant mesh gearsets that resemble manual transmissions. Modern Honda and Acura vehicles have their fair share of transmission options.
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