Quote:
Originally Posted by scrubjaysnest
Have any of you with the Axis/Vegas and 6 speed tranny noticed this?
On a down hill tranny is very quick to down shift if you touch the brakes.
It is slow to up shift after climbing a hill and reaching cruising speed, for us 62 to 65. Worse if in cruise. Doesn't seem to matter if you are towing or not.  |
What would you want the transmission to do differently? Is it limited to upshift sooner without time delay?
Not having driven a 6-speed yet, I'm curious what you would change if you could. Your description sounds fairly typical of shift logic -- downshift quickly to provide immediate engine braking when needed (time delay would not be a good thing because it could lead to brakes overheating or accident), and a time delay (pause) when upshifting to prevent additional shifts in case the road turns uphill again. My guess is that engineers try to program transmission so that if you're climbing in a lower gear, and the road levels off for just a little distance, and then turns up again, that you don't end up upshifting on the flat, and then immediately downshift again. I think drivers would find unnecessary multiple shifts even more annoying.
For what it's worth, in the future (I would guess maybe 5 years ????) many vehicles will use GPS to identify road conditions (including grade and elevation) ahead of time so that the next gear needed will be anticipated before the vehicle gets there. That should allow for more efficient transmission programming while eliminating unnecessary shifts.
In the past, when fuel economy wasn't as important, engines ran at partial load more so, so having too many shifts up or down wasn't as big a problem. Gasoline engines today usually operate closer to full throttle for higher efficiency, so when a steep grade is encountered, it requires a downshift more often than in past.
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