cflury

<o:smarttagtype namespaceuri="urn:schemas-microsoft-com<img src=" http:="" g35driver.com="" forums="" images="" smilies="" redface.gif="" border="0" alt="" title="Embarrassment" smilieid="3" class="inlineimg"></o:smarttagtype>Hey all,
I just picked up my G37 Sedan <st1:city w:st="on"><st1></st1></st1:city> on Friday and have been experiencing a weird issue with the down shifts while breaking. Slowing from 80Mph through 23Mph is nice and smooth but right around 23Mph my RPMs jump to over 2k and there is a sudden de-acceleration to 20Mph. Sort of a jolt almost. I can feel that the downshift it occurring there and the engine takes over breaking for a second as it brings down the RPMs. Anyone else noticed this?
~Flury

pfizzle

iTrader: (2)

Search Flury, search.

This is normal.

RedG37SNC

And should get smoother after your first oil change and both transmission and engine break in.

cflury

Hey all,
I am taking my car in tomorrow and they are going to look at it, also getting them to install the Illuminated Kick Plates while they have it. I really love this car.
~Flury

cao_123

I have the same slightly rough downshift issue. The dealer was able to duplicate the issue but they say all of the G37s behave this way. As far as they know, there aren't any fixes out but if enough people complain they'll likely develop a software fix.

SkyMG37x

Considering that the transmission 1st and 2nd gear ratios have large differences from their next gear up, this is not abnormal although it's not surprising that some people find the downshift rougher than expected. Personally I notice these last 2 downshifts more than the higher gears but no more than my previous 6 speed C5.

PeterUbers

iTrader: (1)

the hardest shift is actually 3-->2

yld2rob

Congrats on the new car! How about some pics? I ordered Xs and am not looking forward to this issue. I have even thought about canceling the order and going with something else. We are almost an entire model year with this issue. You would think there would be a fix by now.

iiiiiekoiiiii

your car is totalled, There is no hope...

SkyMG37x

If you think it's a defect then definitely look for another car. For people that understand the engineering of this powertrain it's not.

cflury

They said there is a software update coming in a few months. I have pics of the car up in the garage.

terrycs

iTrader: (37)

Were you driving agressively or braking hard in DS mode? If so, it will happen, even in the 5AT. It will clear once it sees you are not driving that way anymore.

terrycs

iTrader: (37)

Has anyone watched your AT downshift by itself in manual mode? No matter how slowly I decelerate, my transmission goes through all the gears, but always skips 2 and goes from 3 to 1. I'm guessing this is to reduce the "jolt" coming to a stop?

cao_123

Do you mind explaining the engineering of the powertrain in simple terms (if possible)? Most of us experience the slightly rough downshift during normal driving in D mode when coasting to a stop at around 20 mph.

I would accept this as a normal sporty characteristic in DS mode but would expect the car to remain smooth in D. However, it does seem to be a "normal" characteristic unless a software update is in our future.

Michelangelo

Search is your friend!

Search of "rough downshift" revealed this little gem:

https://www.myg37.com/forums/g37-sed...cond-gear.html

Enjoy!