Engine, Drivetrain & Forced-Induction
Have Technical Questions or Done Modifications to the G37? Find out the answer in here!

Transmission down shifting issue - Fuzzy logic

Thread Tools
 
Search this Thread
 
Old 09-10-2010, 05:20 PM
  #16  
terrycs
Registered Member
iTrader: (37)
 
terrycs's Avatar
 
Join Date: Dec 2006
Location: Southern California
Posts: 1,337
Received 9 Likes on 9 Posts
DS actually behaves like D until the car senses "agressive" driving, then the transmission shifts aggressively. BUT, it calms back down after a complete stop and will drive like D again.

example 1: if you are in DS mode and make a fast stop while doing 65mph, your tach will jump through the roof (possibly giving your passenger a heart attack). but it will behave again after you have come to a complete stop and begin moving again.

example 2: if you are in DS mode and accelerate "normally", the car will behave like it is in D mode shifting through all gears (at least in my 5AT). But if you nail the gas from a dead stop, the car will hold the gear all the way to redline before shifting. I don't reacall mine ever shifting into 5th while doing this (because I've already accomplished what I wanted to do by 4th gear), so I'm not sure what will happen in the 7AT.

DS works in stop and go as long as you know what will happen, but I prefer the paddles.
Old 09-10-2010, 10:59 PM
  #17  
XILAR8N
Registered User
 
XILAR8N's Avatar
 
Join Date: Oct 2009
Posts: 63
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Mike S.
Yea, sounds like the tranny is working fine.....fuzzy driver.

I agree...
Old 09-10-2010, 11:06 PM
  #18  
PascalT
Registered User
 
PascalT's Avatar
 
Join Date: Mar 2010
Location: Montreal
Posts: 322
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by sniper27
DS mode is not meant to be used in a traffic jam.
hmm so? Does that mean the car is suppose to jerk around while the car is staying still? Pretty sure that's not how it should react.
Old 09-10-2010, 11:11 PM
  #19  
RedG37SNC
Registered User
 
RedG37SNC's Avatar
 
Join Date: Dec 2007
Location: Charlotte, NC
Posts: 2,112
Likes: 0
Received 4 Likes on 3 Posts
Think that's bad, when you step on the gas the car goes faster, let up and it slows down. Damn I should have got the TL.
Old 09-10-2010, 11:38 PM
  #20  
hadokenuh
Registered User
 
hadokenuh's Avatar
 
Join Date: Jun 2009
Posts: 535
Received 4 Likes on 4 Posts
I think when Acura, Lexus and Infiniti merge into one company, you'll be able to "build your own car" by selecting everything from exterior, engine, transmission, interior... Then there will be less complaints

Seriously, the DS mode is great. If you have to complain something about it, it should be the delay when you go from D to DS and immediately floor it. Other than that, I love the mode.
Old 09-16-2010, 11:02 PM
  #21  
use2vw
Registered User
iTrader: (2)
 
use2vw's Avatar
 
Join Date: May 2010
Posts: 156
Likes: 0
Received 2 Likes on 2 Posts
This goes beyond engine braking...the 2-3 shift in DS can sometimes be like a sloppy clutch dumpped shift = huge jerk (I actually thought someone tapped my bumper the first time it happened). I only drive in DS when in local and save D for grandpa highway floating... the 7at programming SUX! DS mode is trying to be sport and hold gears (and even then, it lags sometimes) try to pass in jus D forget it - you have better change ina VW GTI...sad. A $40+k car trans has no shot vs my old $20k+ TSX trans...lesson learned go 6spd man next time...
Old 09-18-2010, 08:47 PM
  #22  
bacid
Registered User
 
bacid's Avatar
 
Join Date: Apr 2010
Posts: 16
Likes: 0
Received 0 Likes on 0 Posts
i agree, the downshifts are very jerky and aggressive.

i was in a friends c63 amg recently which has significantly more hp than our g37's and it was nowhere near as jerky as ours.

it';s got nothing to do with "sportiness" or hp, it's poor programming which needs to be fixed.
Old 09-28-2010, 05:05 PM
  #23  
blitzebill
Registered User
 
blitzebill's Avatar
 
Join Date: Oct 2009
Location: Ohio
Posts: 244
Likes: 0
Received 1 Like on 1 Post
Originally Posted by BLKG37X
I really enjoy the DS mode, but I always worry about causing damage to the car. It cant be good to constantly reving it up to 5K
++++


don't let it go that high, i shift around 3K with even pressure on the gas and the car responds beautifully.
Old 09-28-2010, 10:05 PM
  #24  
mooshoofooie
Registered User
iTrader: (1)
 
mooshoofooie's Avatar
 
Join Date: Sep 2010
Location: Houston
Posts: 28
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by terrycs
DS actually behaves like D until the car senses "agressive" driving, then the transmission shifts aggressively. BUT, it calms back down after a complete stop and will drive like D again.

example 1: if you are in DS mode and make a fast stop while doing 65mph, your tach will jump through the roof (possibly giving your passenger a heart attack). but it will behave again after you have come to a complete stop and begin moving again.

example 2: if you are in DS mode and accelerate "normally", the car will behave like it is in D mode shifting through all gears (at least in my 5AT). But if you nail the gas from a dead stop, the car will hold the gear all the way to redline before shifting. I don't reacall mine ever shifting into 5th while doing this (because I've already accomplished what I wanted to do by 4th gear), so I'm not sure what will happen in the 7AT.

DS works in stop and go as long as you know what will happen, but I prefer the paddles.
i beg to differ, atleast with my 7AT. Once it's in Ds mode, it won't shift until it reaches 4-5rpm unlike shifts at 3krpm in Da mode, both with same gas pedal pressure. so from the drive mode shift, the computer behaves differently.

Originally Posted by RedG37SNC
Think that's bad, when you step on the gas the car goes faster, let up and it slows down. Damn I should have got the TL.
lol. you would have a better navi too.

Question to all. In Da mode when approaching a stop light at about 40mph, i light break to about 25 and coast until i need to break again. During the coast, it feels like the tranny prematurely shifts from 4th to 3rd (i think, or else it's 3 to 2) i expect some rpm jump, but it almost makes my head hit my headrest every time. my foot is on the break the whole time, just not depressing a lot. wondering if anyone else has this happening.
Old 09-29-2010, 09:25 AM
  #25  
KLB
Registered User
 
KLB's Avatar
 
Join Date: Mar 2009
Location: Chicagoland
Posts: 700
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by mooshoofooie
Question to all. In Da mode when approaching a stop light at about 40mph, i light break to about 25 and coast until i need to break again. During the coast, it feels like the tranny prematurely shifts from 4th to 3rd (i think, or else it's 3 to 2) i expect some rpm jump, but it almost makes my head hit my headrest every time. my foot is on the break the whole time, just not depressing a lot. wondering if anyone else has this happening.
The earlier 2009s did that. There was a TSB for it, which some people did not like because they say it changed the overall way the transmission worked. Cars produced after something like April/May 2009 came with the software update from the factory.
Old 09-29-2010, 09:28 AM
  #26  
KLB
Registered User
 
KLB's Avatar
 
Join Date: Mar 2009
Location: Chicagoland
Posts: 700
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by mooshoofooie
i beg to differ, atleast with my 7AT. Once it's in Ds mode, it won't shift until it reaches 4-5rpm unlike shifts at 3krpm in Da mode, both with same gas pedal pressure. so from the drive mode shift, the computer behaves differently.
This will change as you drive it more. My DS mode is now very similar to my D mode when I am not pushing it. If I start pushing it a little though, it is more responsive and will hold the RPMs higher than D will. I actually like the way the transmission reacts better now than when I first got it.
Old 09-30-2010, 12:12 PM
  #27  
tliao5
Registered User
 
tliao5's Avatar
 
Join Date: Sep 2010
Location: Chicago
Posts: 26
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by mooshoofooie
Question to all. In Da mode when approaching a stop light at about 40mph, i light break to about 25 and coast until i need to break again. During the coast, it feels like the tranny prematurely shifts from 4th to 3rd (i think, or else it's 3 to 2) i expect some rpm jump, but it almost makes my head hit my headrest every time. my foot is on the break the whole time, just not depressing a lot. wondering if anyone else has this happening.
My 2010 Journey sedan does the same thing. I know there is a fix for the 2009's, but I don't think there's anything out there for the 2010's.

It takes a bit to get used to, but it's still a bit annoying.

BTW, I'm new to the forums. Been driving my 2010 G37 for 3 weeks and I LOVE it
Old 09-30-2010, 02:24 PM
  #28  
cvroom
Registered User
 
cvroom's Avatar
 
Join Date: May 2010
Location: Chicagoland, IL
Posts: 507
Likes: 0
Received 2 Likes on 2 Posts
Originally Posted by tliao5
It takes a bit to get used to, but it's still a bit annoying.

BTW, I'm new to the forums. Been driving my 2010 G37 for 3 weeks and I LOVE it
are you talking about D or DS? my 2010 used to downshift aggressively but it has not done that in months. The transmission adapts to your driving habits.
Old 09-30-2010, 02:30 PM
  #29  
tliao5
Registered User
 
tliao5's Avatar
 
Join Date: Sep 2010
Location: Chicago
Posts: 26
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by cvroom
are you talking about D or DS? my 2010 used to downshift aggressively but it has not done that in months. The transmission adapts to your driving habits.

It does it in both D and DS, but it's more pronounced in DS.
Old 10-02-2010, 01:39 AM
  #30  
dbg37
Registered User
 
dbg37's Avatar
 
Join Date: May 2009
Posts: 48
Likes: 0
Received 1 Like on 1 Post
This is an old topic. Search the previous threads. The 7at has very steep gears 1-3 and this downshift is going to be apparent. There is a reason for it, low end torque for the 3.7 is not going to be like a 6 liter v8, so they compensate with gearing.
If you were somehow to allow 4th to stay engaged to under 25 mph and then need to resume speed it would stumble all over itself trying to get into the proper gear, so that is why the seemingly agressive downshift pattern.

Ever try taking off hard from a stop at a corner and having the rear tires break loose at the 1-2 shift before you can get more than 50ft?
CLOSE, STEEP lower gears.
This car might actually would have been more driver friendly with a 6at and more widely spaced gear pattern. But I will take what I have.

I somewhat envy the manual for driving purposes, but my knees appreciate the AT.


Quick Reply: Transmission down shifting issue - Fuzzy logic



All times are GMT -4. The time now is 05:51 PM.