I bought a CPO 2010 G37x sedan in May 2013 and from the start noticed all the same transmission issues noted in these 147+ pages of posts to this tread. (Acceleration lag, excessive engine breaking, feeling of resistance when accelerating at slow speeds forcing you to push harder on the gas pedal, rough 2>1 downshifts, etc.)

Took my G37x to the dealership to get serviced and told them the exact issues noted above. They applied the ITB12-027D update and it drives like a completely different car. Pedal is more linear and power is more immediate when stepping on the gas. The differences are night and day. I HIGHLY recommend that anyone even slightly annoyed with the transmission get this update done ASAP. It was free too because I'm still under warranty.

 

Does anyone know what each of the revisions of the 027 TB (rev a,b,c,d...etc)? Has there been something newer that rev D? I drove a 2013 loaner G37 and it seemed to be much more crisper than my 2011 with the 027 tsb.

 

I notice all the bugs you guys talk about and it directly relates to me feeling like a boat is behind this car when I let off the gas and the incredible amount of drivetrain 'drag'.

But, my car is a 2013 and they say it is as updated as it can go. Anyone have any suggestions?

 

I've been in many g35 and g37 sedans before I picked up mine on Monday and I noticed after the first day that the transmission was jumpy when shifting from 2-3 and 3-4. Also, was very rough on the downshifts. I took it to Infiniti and they applied an ECU update as well as the transmission update.

My G37x drives much smoother after the two updates, even with the transmission being in full learning mode after getting that update. I'm liking the results so far and when it adapts to how I daily drive, I'm sure it will feel like butter.

 

I finally reflashed the stock programing on my 09. I've held off till now since I can get my car to downshift quickly by pressing down quickly on the gas about 1/4 of the way down. The harsh downshifts have never bother me either.

But my wife is not a fan of the harsh downshift which my car still has. This was the main issue with the 09's when they came out with the new 7AT. Anyway got tired of the wife complaining about the harsh downshift and to shut her up had it done today. She's been using the G more regularly as of late. Usually the G is my daily driver and till recently she had only driven the G a couple of times. .

My dealer was great. I did not have to fight or prove it to them that my car had the harsh downshift issue. I just mentioned the symptoms and they told me they would reflash my gearbox with the latest software version .027d.

Don't know if it fixed the harsh downshift issue. But the gearbox feels a lot more responsive and sporty in D compared to before. I mainly drive in M in the hwy, but will try D for next couple of days to compared it to the original 09 programming. So far I like it.

[Update]

Been driving the car now for 3 days since the reflash in D only. I've been driving my G almost as hard as the loaner and so far it's been great. Have not use M once and don't see a reason to use M as much as used to. Have not use DS either. The harsh downshift issue is pretty much gone. The car is now is very aggressive and sporty in D mode. Feels like I got a new car.

 

I take my car in tomorrow to have this update done because i have the harsh downshifts, lag when trying to accelerate and i get the 2nd to 3rd shift flare.

Has anyone noticed an rpm flare while just cruising down the highway? I have started to notice this more and more lately. I will be driving around 65-70mph on a flat road and the rpms all of the sudden just jump up for 5 seconds then i can watch them go back down, almost like it shifts into 6th gear and then back into 7th. Has anyone else ever noticed this?

 

I kind of think i know what your saying. This is my flare situation:


does this new TSB correct the "flare" in the transmission? where sometimes the rpm will jump up around 250-500 rpm between shifts (feels like a slipping tranny or locking and unlocking of the torque converter to early). mostly does this when you drive the car a bit then park for a little then drive again. It doesn't happen all the time, but it sure is annoying when it does!

I hope someone can chime in because they are having/know about the problem.

Also, has any member (from minnesota) here had the new 027d done? If so, what dealership

 

Is there anyway to have Infiniti check to see if this upgrade has been done before being in for the service (VIN lookup)? I just purchased a 2010 G37s and have noticed some odd transmission habits similar to what everyone is describing. Just wanted to see if I could figure out if this was done previously so when I get there they dont tell me its already been done.

 

I just had the TSB done on my 09 G37xS last weekend. I had this "flare" mostly when the car is shifting from 1-2 first thing in the morning. But also have had it randomly do that as you said when the car was driven and then off and then driven again. So far with the new program my car has not done any of this at all.

I am really happy with the update so far, but am waiting to see if the auto learn feature eventually ruins the behavior of the transmission again.

 

Just got mine back from the dealer tuesday, TSB reflash of the trans under warranty of course... night and day, smooth acceleration, no lag, no drag, no excessive braking. Love it!

 

@Jethro:

Is your car still under warranty? Did dealer charge you to do this TSB?

 

My car is still under warranty, so no charge from the dealer. I think if you are out of warranty they would probably charge you, but I could be wrong.

 

Just picked up my coupe today after having the ITB12-027D update done. I agree it makes the car drive a lot better! No more harsh downshifts = Couldn't be happier now.

 

Would this still happen to 2011 model, I feel my car has the same symptoms.

 

There is an update for 2011, I had mine done about 2 weeks ago and it performs a lot better now.