I have a 2017 cx-5 GT awd. The car shifts super smooth and all is good, but after the up shifting of the transmission, there is sometimes a drop or it raises a touch on the tachometer. It's after the tachometer drops initially after the shift. It's sometimes like a flutter on the tachometer and it can be enough to notice it if your watching this. It usually only happens when driving at a slower pace. If I push the car, it shifts fast and doesn't flutter. Anyone else experience this? Cliff notes: tachometer drops after the upshift, then there can be a slight rise/drop that is noticeable again right after
Tachometer movement after shift
- Thread starter 17CX-5GT
- Start date
My guess would be that you're noticing the torque converter lock up.
That could explain the slight drop (if you're slowly accelerating) and slight rise (if you're not accelerating)
During quicker driving, smoothness is not as much of a priority so the converter might lock up too quickly for you to notice.
I agree it's the torque converter. This transmission definitely feels very much like a DCT a lot of the time but there is a torque converter that in some circumstances will unlock and lock.
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- 23 CX-5 Premium
are you sure? I thought it just very quickly locked an unlocked for every shift? (kind of like a clutch in a manual)
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- 23 CX-5 Premium
The only time the T/C operates on the Skyactiv 6at is under 5 mph to smooth out start ups, gridlock traffic and parking maneuvers. Othwise it never comes into play. Try climbing a relatively steep driveway from a dead stop at the bottom. By the time you reach the top, you can easily have reached 5 mph and you can actually feel the converter lock. Feels kind of clunky; took me a while to get used to that. Now I just expect it.
BTW, the converter doesn't function as a clutch in the 6at. There's an actual clutch that performs that function!
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I can't find a good source, but shifting with the torque converter clutch locked up is a bad idea.
That would require the small clutches/brakes inside of the transmission to do all of the work slowing the engine down (even at WOT) between shifts.
Instead, the TCC quicly unlocks, the transmission shifts with limited load and the TCC locks up right after the shift is complete. The torque converter clutch on the skyactiv is a heavy duty multi plate clutch, while the clutches inside the transmission are small and not designed can't take the full load of a shift (you can almost think of them as synchronizes).
I think the Skyactiv AT does use the clutch vs torque converter at higher speeds. Regardless as the engine is disengaged, other clutches do their sync thing, and then re-engaged I don't think it would be unusual for the tach to vary a bit as the ECU also is rev matching. Probably nothing to worry about.
I would add the car we traded for the CX-5 and a DCT. As it would shift you could see tach jump up or down and sometimes overshoot a bit and then drop back as the DCT would more gently engage the clutch. Basically as it's slipping a bit it's higher then as it bites it drops back down. If the computer just "dropped the clutch" causing fast abrupt engagement it would cause more driveline shock and be unpleasant to the general motoring public.
As other's have mentioned. The Skyactive transmission has a torque converter and a larger, more capable clutch pack that a typical auto transmission.
The transmission uses the torque converter for smooth shifting under light loads and uses the clutch pack to lock up the torque converter for effeciency and performance over a much wider range than a typical auto.
What you're seeing is the lock-up activating / de-activating. All is good with your car.
http://www.mazda.com/en/innovation/technology/skyactiv/skyactiv-drive/
https://www.youtube.com/watch?v=6h4GDaUP7gA
