3>2 downshift
Safety Car
Joined: Mar 2009
Posts: 4,101
Likes: 719
From: Northeast MA & Mad Beach FL
One of the annoying things I find about the way the A6 transmission is programmed is the 3>2 downshift.
Lets say you're trying to pass a car at about 50-60mph. You push on the gas to go around. The car doesn't respond as quickly as you need it to, so you keep pushing on the pedal. As you pass about about 80% throttle on the TPS sensor and 63 mph the car now downshifts all the way to second gear. The result is instant tire spin and engagement of the traction control, which pretty much shuts the car down while you are in mid pass. To say the least, this is more than just a little dangerous. It can get you killed if you aren't careful.
I'm starting to think that the problem is that GM programmed the car to downshift one gear too far, and that the speeds at which the programing on the transmission for 3>2 downshifts is too high. If you take the throttle all the way to the floor (100% on the TPS) the car will downshift to 2nd gear all the way to around 85mph. A second gear downshift at 85mph is asking for trouble. Not to mention how hard it is on the transmission.
GM needs to rethink the programming on the transmission. The car should deliver a linear and predictable power increase from the transmission and engine and it should progressively downshift one gear at a time as you push on the pedal. The instant 4 gear downshift that can occur when you go from cruising at 55mph in 6th gear to 2nd gear results in too drastic of a power increase. I believe they should drastically lower the max speeds at which the car will downshift to 2nd gear to around 40mph. The way the A6 is programmed now, it pretty much makes it impossible to safely take the gas pedal to the floor at any speed over about 30mph.
I'd like to hear others thoughts on this. Have you ever been surprised by the 4 gear downshift at speed when you go to pass another vehicle?
Lets say you're trying to pass a car at about 50-60mph. You push on the gas to go around. The car doesn't respond as quickly as you need it to, so you keep pushing on the pedal. As you pass about about 80% throttle on the TPS sensor and 63 mph the car now downshifts all the way to second gear. The result is instant tire spin and engagement of the traction control, which pretty much shuts the car down while you are in mid pass. To say the least, this is more than just a little dangerous. It can get you killed if you aren't careful.
I'm starting to think that the problem is that GM programmed the car to downshift one gear too far, and that the speeds at which the programing on the transmission for 3>2 downshifts is too high. If you take the throttle all the way to the floor (100% on the TPS) the car will downshift to 2nd gear all the way to around 85mph. A second gear downshift at 85mph is asking for trouble. Not to mention how hard it is on the transmission.
GM needs to rethink the programming on the transmission. The car should deliver a linear and predictable power increase from the transmission and engine and it should progressively downshift one gear at a time as you push on the pedal. The instant 4 gear downshift that can occur when you go from cruising at 55mph in 6th gear to 2nd gear results in too drastic of a power increase. I believe they should drastically lower the max speeds at which the car will downshift to 2nd gear to around 40mph. The way the A6 is programmed now, it pretty much makes it impossible to safely take the gas pedal to the floor at any speed over about 30mph.
I'd like to hear others thoughts on this. Have you ever been surprised by the 4 gear downshift at speed when you go to pass another vehicle?
When I first had mine it did some wild things when pushing too fast and too far on the gas pedal.
I got used to Not pushing to fast or too far on the pedal and it works just fine now.
Cruising on the highway and going to pass, just "roll" the pedal down and the trans will Progressively down shift and accelerate.
Once it hits 3rd, it's pretty much going fast enough already and I stop pushing the pedal down and let it accelerate from there.
3rd is good for over 100
In my experience the only time it would go into 2nd is when I got impatient and pressed it further.
Now I find no need to press it further since these cars are already going a lot faster than they seem.
And when it does hit 2nd, the revs are already so high, it shifts right back into 3rd and it's a wasted downshift.
When entering the highway off a exit, I'll roll the pedal down until it does hit 2nd and since the car is not doing 50 or 60, it's a much more controlled downshift with more room for the revs to climb before it shifts to 3rd.
Just my thoughts
Pro
Joined: Aug 2008
Posts: 694
Likes: 3
From: West Linn OR
When I first read the post I was going to mention that he needs to get a tune
But now WTF is going on?
Is Fred suffering from lapse of memory since he forgot to mention he has had not one but two tunes?
And now:
Quote:
Originally Posted by Chevy Cust Svc
Fred,
Thanks fior the feedback. I'm going to document this. Please don't hesitate to contact us with questions, comments or concerns.
Chevrolet Customer Service,
Justin
Le Mans Master
Joined: May 2005
Posts: 6,656
Likes: 823
From: FORT LAUDERDALE FL
I don't recall if the OP stated that he was in D or S when this happens........FWIW.
