G37 Transmission Issues with 4th -> 3rd Downshift

[slickd8]

Originally Posted by JayDeePee

I am curious as to what is the build date of your G37? My G37's build date is 07/09. I just got the car 3 weeks ago with 9 miles on the odometer. I am wondering if the Transmission was flashed with the new software. I haven't noticed the downshift problem, but it does seem like at 30 to 40 mph the transmission searches between 3rd and 4th gear. Should I just take it to the dealership and have them look at it?

My car build date is 08/09. Like Silver37 described, on loaner car, it does a engine break around 20mph, and throw my head forward unexpectedly. To make matter worse, that is when I normally press my break too, so I get double breaks. After a few of those, my head was a bit dizzy.

I don't feel my new car hunting gears between 30 to 40 mph. It is very smooth so far.

[Mike S.]

I'm not sure why everyone is talking about smoother upshifts etc. I think this is all in your head folks. The tcm flash was to fix the rough 4-3 downshift...thats it. And rough isn't even the right word. It was never rough...just it happended to soon (probably with the torque converter locked) and it produced agreesive decceration...but it was never "rough".

This goes back to my friends in the mid 90's when lots of cars had overdrive on/off bottons. People SWORE their car was faster with overdrive off....not highway speeds..but city driving. Noboby could understand that it just locks out 4th gear (most were 4sp auto's then). Yea...if you're going 50 mph..then sure...its in 3rd and not 4th...but off the line? 1-3 gears....its the same car.

All of these posts remind me of that.

PS sorry for the rant.

[Silver37]

Originally Posted by Mike S.

I'm not sure why everyone is talking about smoother upshifts etc. I think this is all in your head folks. The tcm flash was to fix the rough 4-3 downshift...thats it. And rough isn't even the right word. It was never rough...just it happended to soon (probably with the torque converter locked) and it produced agreesive decceration...but it was never "rough".

This goes back to my friends in the mid 90's when lots of cars had overdrive on/off bottons. People SWORE their car was faster with overdrive off....not highway speeds..but city driving. Noboby could understand that it just locks out 4th gear (most were 4sp auto's then). Yea...if you're going 50 mph..then sure...its in 3rd and not 4th...but off the line? 1-3 gears....its the same car.

All of these posts remind me of that.
PS sorry for the rant.

Mike, you ARE getting way too emotional about this topic! Don't assume that a fix for the 4-3 downshift wouldn't have included other tweaks to the engine/transmission syncing. My 1-2-3 upshifts are way better now. Before the upgrade, mine would spin up in 1st gear way too long before changing to 2-3. This actually made the car accelerate slower than most other cars until I hit 3rd when it really took off. I assumed Infiniti had made a super low 1st gear to keep the car from taking off so abruptly like previous generation Gs. The latest flash does a much better job of timing the 1-2-3 shifts to take advantage of each gear, staying in 1 and 2 only long enough to launch the car. You'll notice this mostly if you use minimal throttle to get the car going. You probably won't notice this if you tend to give it more gas when you accelerate. I really like the upgrade. My only complaint is that it still has some flair under some conditions. Maybe they'll fix that next time around.

[botosoft]

Hello, folks. First post.

Just got my G37S Journey on 28 October. Didn't take me long to notice the car was engine braking - rather than simply coasting - a helluva lot.

Question is - Should I wait until I've put more miles on the car before bringing it back to the dealership? Just 300 miles on the odometer.

[Mockenrue]

As I understand it, the update doesn't stop the engine breaking. My dealer told me that I had the latest flash, and mine still engine breaks on coast. It's not just a "feature" of this transmission. I used to have an Altima that did the same thing, and it has a CVT without gears, per se.

[Silver37]

Originally Posted by Mockenrue

As I understand it, the update doesn't stop the engine breaking. My dealer told me that I had the latest flash, and mine still engine breaks on coast. It's not just a "feature" of this transmission. I used to have an Altima that did the same thing, and it has a CVT without gears, per se.

Correct - the update doesn't stop it, but makes it much more manageable. I like it with the fix - just the right amount of engine braking. One cool feature is that it will downshift on long hills if you keep applying the brakes. That is an awesome/unexpected feature.

[botosoft]

Thanks for sharing your experiences, guys. I appreciate it.

This engine braking on an auto is new to me. Quite unnerving. Sometimes, it I swear it feels like driving with the hand (foot?) brake on.

I guess I'll log in a few more miles to gain a little more experience with the car before deciding whether to take it back to the dealership. It's not like doing so is drudgery, eh?

[Silver37]

Originally Posted by botosoft

Thanks for sharing your experiences, guys. I appreciate it.

This engine braking on an auto is new to me. Quite unnerving. Sometimes, it I swear it feels like driving with the hand (foot?) brake on.

I guess I'll log in a few more miles to gain a little more experience with the car before deciding whether to take it back to the dealership. It's not like doing so is drudgery, eh?

I put off going to the dealership for a long time due to my schedule and past experiences with dealers, but my experience was great. They were exceptionally professional and did a great job on fixing several items.

[gugarci]

I have never had my car re-flash as my downshifts are not too bad and have definitely smoothen out since my car now 6K miles. My wife has never complained about this issue and she has driven the car many times in the past. In fact she never notice it till I pointed out and said it was no big deal. That surprise me.

The only thing I don't like about this gearbox, and this might be do to my driving style, is the transmission spends too much time while cruising at really low RPM's.

A lot of time while driving leisurely around town and on country roads where the speed limits are 45mph my RPM's are usually 1100,1200 range.

But again this could be related to the ECU having adjusted to my relaxed style around town.

[newg37ontheroad]

I went to my dealership today. Mine is '09 G37 manufactured in Aug 09. The sales manager cross checked my VIN and told me my car is eligible for the TSB. I talked to the warranty dept. and they said just because it's eligible it does not mean I have a older firmware in the TCM. It may or may not be old. I wanted a tech to hook up the C-III to the TCM and just check if the update is reqd. cause I'm unsure if my car needs it since it was mfged in Aug 09 even though it's eligible. I have just crossed 1000 miles today and want to drive till the first oil change to see if it smoothens out.

The warranty dept. will not let a tech hook up the C-III just to see if mine is updated or not cause they said they cant justify the work to Infiniti. They will either have to download or not required to download the update (if it doesnt need one). This has been my experience today.

What do yall think of this? I feel a little engine break right at 30mph when downshifting.

[mw09g37]

even tho your car doesn't check out, the diagnosis is still valid.

Even though the TSB doesn't apply to the car (ie axle clicking on the g35sedan applied to the g37 sedan but there wasn't a TSB for it)

I don't see how they'd have an issue with applying the ITB if they can diagnose the issue.

if they still don't do it go to another dealer. the 4-3 was pretty rough at its worst.

[newg37ontheroad]

Originally Posted by mw09g37

even tho your car doesn't check out, the diagnosis is still valid.

Even though the TSB doesn't apply to the car (ie axle clicking on the g35sedan applied to the g37 sedan but there wasn't a TSB for it)

I don't see how they'd have an issue with applying the ITB if they can diagnose the issue.

if they still don't do it go to another dealer. the 4-3 was pretty rough at its worst.

Well what they are saying is once they hookup the C-III they will have to complete the download of the updated firmware if my car needs one. If it doesn't require it (just because it was manufactured in Aug 09) then nothing needs to be done. But they just dont want to hook up the C-III and see what I got. They cannot justify the labor to Infiniti for that effort which is what I was looking for.

I don't know if that sounds strange or if that makes sense? Not sure if another dealership (where I didn't buy my car) would do this.

[botosoft]

Originally Posted by gugarci

The only thing I don't like about this gearbox, and this might be do to my driving style, is the transmission spends too much time while cruising at really low RPM's.

A lot of time while driving leisurely around town and on country roads where the speed limits are 45mph my RPM's are usually 1100,1200 range.

But again this could be related to the ECU having adjusted to my relaxed style around town.

I read that last bit, curious about the ECU "adjusting" my driving style, and sure enough, the engine breaking issue I head became less pronounced with just about 600 miles on the odometer.

I guess I'm headed towards low RPMs too, since most of the time I'm simply trying to get from point A to point B in style.

Downshifts are not egregiously bad. Maybe it has something to do with my early-ish 02-09 manufacture of my sedan?

Mileage sucks bad, though. Hope the expected fuel economy improvement shows up after the engine break-in. Getting just 16 MPG feathering the throttle.