I've noticed the rough downshift as well. It's not too bad but I'm hoping for a fix. The dealer in Baton Rouge, LA hasn't heard anything about an ITB.

 

I've noticed the rough downshifts for a while and thought it was how I was braking LOL. I drive in traffic to and from work and notice it ALOT. I will have to call about this "update"

 

Mine only downshifts hard in DS mode and I kind of liek that. In D, I dont feel anything...

 

According to the following discussion, that service bulleting ITB07-048 is for the 2008 G37 coupe.
http://x.infinitihelp.com/forum/show...19.html?t=1819

Here is a complete list of service bulletins for the 2009 G37 sedan that I found on infinitihelp.com. I don't see anything related to the transmission.
http://x.infinitihelp.com/forum/loca....php?catid=302

I have a little less than 400 miles on my 12 day old 2009 G37xS sedan and I'm definitely experiencing the rough downshift between 3rd and 2nd gear. It's very unnerving.

 

I've had my G37x for about a week, and I've noticed the downshifting too. It's not that surprising to me though, because my 07 Altima did the same thing with the CVT. I like the engine breaking about 75% of the time, and it does save on brakes. The worst is when you're trying to coast down a hill and you have to keep hitting the gas.

I asked my dealer about it and they said there was no official bulletin, but they are aware of it and know how to reprogram for anyone that conplains. I'm going to wait and see how it goes for a little more break-in.

 

I purchased a G36 sedan 3 weeks ago. I have this rough downshift. I took it to Sewel Infiniti in North Houston. They did not have any solution. I provided the ITB info from 2008. They tried reprogramming my ECU but car has latest update.

To those that had their cars fixed with update, any more details would be appreciated.

 

[quote=PeterUbers;2622355]Every once in a while i'll be coasting with foot off the pedal (say, at about 20 mph) and i'll jump on the throttle and feel like i caught the gears changing and it'll clunk (felt, not heard) a little, but this is once in a blue moon .. and every once in a while i'll feel a subtle down shift as I brake to a stop .. nothing major and definitely nothing that bugs me.

Mercedes owners with 7AT's experience same things...

Our '99 Audi A6 quattro has always done this - same exact scenario & still running fine at 99,000 miles.

 

going to get this done next time im in for an oil change.

 

I have a 7AT G37 sedan, and I've been experiencing this same problem sporadically ever since I got the car in February 2009. I took the car in today for its 7,500 mile service to West Houston Infiniti and they said that they've never heard of the problem and that they follow Infiniti's lead on such things. Therefore, they wouldn't do anything other than check it out and ensure that all updates have been made that are available through Infiniti. The service tech said that there isn't a TSB on this issue. When I picked up the car, he said that the service guys test drove my car and 4 other G37s and they all drove similarly. He said that all of the gearing checked out to factory specs. Oh well, I guess I'll just have to suck it up for now and continue to hammer away until a resolution comes.

 

The more I drive this car the more I realize i really am not worried about it -- i'm too busy enjoying the rest of the driving experience.