Transmission Issues - slipping, slamming, mis-shifting

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Transmission Issues - slipping, slamming, mis-shifting

Postby EdBwoy » Thu Jun 06, 2019 6:23 pm

I have seen mention of transmission issues from some owners. My suspicion is that the issues are more than beyond the behavior of the 7 speed wanting to constantly hunt for gears.

I know there was a TSB/reprogram of the TCM that can help level things out. Not forgetting a hard reset which ends up relearn of the modules.

I suspect some correlation and would like to dive deeper into my theories. Your participation will be appreciated:
1. Do you feel like your transmission behaves funny, especially in city driving?
2. What year is your car?
3. Is it a V8 or V6?
4. RWD or AWD?
5. Are you the original owner? Has it always behaved like this or did a specific event trigger these issues?
6. What solutions have you tried so far, and did it improve?


Brian35XR
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Re: Transmission Issues - slipping, slamming, mis-shifting

Postby Brian35XR » Thu Jun 06, 2019 7:20 pm

Yes among the countless reports you can find on other infiniti and g37 forums I feel like my transmission has some rough behaviors for a smooth transmission.

1. Definitely behaves funny in city driving. my biggest complaint is a hard "clunk" downshift at random in city driving. Also the car seems to have a habit of upshifting right when i press the gas hard leaving me with no power.

2. 2011
3. V6
4. AWD
5. Third owner. Always behaved like this.

6. I've tried a ECU reset which I don't feel like improves much. My friend has a G37Xs and actually had the transmission re-programmed at the dealer to the newest update per the TSB which he said made it felt like a brand new car. After a while, he complained the car was re-learning it's old bad habits. I did the ECU reset to his car and he said it fixed it again. The dealer probably just did the same for all he knows..

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Re: Transmission Issues - slipping, slamming, mis-shifting

Postby cliffyk » Fri Jun 07, 2019 2:19 am

I just today noticed a couple of hard downshifts during a quicker than normal slow-down/stop in traffic. I was traveling 35 mph or so and had to slow/stop somewhat rapidly, just after accelerating from a light. In Sport Mode, 107k miles on the car, tranny juice changed at 103k. I believe the the reprogramming had been performed by the PO. I reset the learned behaviour at 104k or so. I think my "hurry up", now "slow/stop" maneuver may have confused the transmission control module--not overly concerned at this point.

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Re: Transmission Issues - slipping, slamming, mis-shifting

Postby mazz » Fri Jun 07, 2019 4:55 am

2013 v6 awd fortunately i have not experienced transmission issues at all

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Re: Transmission Issues - slipping, slamming, mis-shifting

Postby ArmedAviator » Fri Jun 07, 2019 6:52 am

1. Funny? No. Less than ideal shifting schedule? Yes.
2. 2012
3. V6
4. AWD
5. No, second owner.
6. If I intend on taking a corner quick and applying gas in the turn, I downshift manually into the gear I want to accelerate with using paddle shifters or shift knob and then there's no go hunting issues.


With that said, if you understand how an automatic transmission works, you may find these issues aren't really issues - it's just the nature of the beast. Sure, on occasion I get a "hard" shift where it feels like it slams into gear. This is caused by the ECU deciding to shift, deciding the line pressure needed for a smooth-ish shift (how fast it will apply the clutches), and then as it commences the shift, you change the throttle (generally lifting off). When load is high, the transmission will use more line pressure to apply the clutches more quickly so there is less clutch wear and also still maintain a smooth and quick shift. When load is low, the line pressure is low, so the clutches engage more slowly, since the clutches won't slip too much so it will be a smooth shift.

When at a high load (accelerating, for example), the ECU commands high line pressure, then just as it shifts, you let off the gas. Boom, you have no load on the engine/trans, and it is shifting with high line pressure. This is when you get the SLAM into gear.

This is true of all automatics, as far as I am aware.

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Re: Transmission Issues - slipping, slamming, mis-shifting

Postby EdBwoy » Fri Jun 07, 2019 7:08 am

Car #1.
1. 2011
2. V8, M56 sport
3. RWD
4. 2nd owner
5. Has always driven smoothly, no hiccups to speak of.

Car #2, the test mule
1. Has a weirdly shifting trans that some have described to me as "feeling like it's being held back"
2. 2011
3. V8, M56x
4. All wheel drive
5. 3rd owner, it drove like this from the first day I got it with approx 145,000 miles.
6. Based on discussions here, I thought it was something more localized to the V8s and related to the timing chain recall. So I had the dealer check my fluid levels and perform the software update. The improvement was minimal. I did a TCM relearn at home and there was greater improvement in the way it drove. It is still horrible compared to my other M56, so I gave it to an "independent driver for an unbiased opinion" and she also pointed out that it shifted funny in town.

These are 2 of the discussions that pointed me towards fluid level:
- p0420-catalytic-repair-m56x-now-missing ... 23433.html
- post6791092.html#p6788496

It seems it's not isolated to only V8s then. Good. We'll see what Q70 owners have to share

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Re: Transmission Issues - slipping, slamming, mis-shifting

Postby pedsemdoc » Fri Jun 07, 2019 6:11 pm

1. Not in automatic mode, sometimes I get a little bucking when in manumatic mode in 1st/2nd
2. 2013
3. V6
4. RWD
5. 2nd owner - think it's behaved like this as far as I can remember
6. Haven't tried anything


I think other relevant info might include

7. Mileage
8. Has your transmission ever been serviced? when/mileage? and full flush?/drain and fill?

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pedsemdoc
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Re: Transmission Issues - slipping, slamming, mis-shifting

Postby pedsemdoc » Fri Jun 07, 2019 9:09 pm

7. 84k
8. Tranmission flushed by dealer at 67557, over 2 yrs ago

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paranoidjack
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Re: Transmission Issues - slipping, slamming, mis-shifting

Postby paranoidjack » Tue Jun 11, 2019 9:28 am

1. Do you feel like your transmission behaves funny, especially in city driving?
----transmission is generally indecisive, from 40% throttle to 75% throttle it gets confused based upon travel speed.
2. What year is your car?
---2012 M56S
3. Is it a V8 or V6?
---V8
4. RWD or AWD?
---RWD
5. Are you the original owner? Has it always behaved like this or did a specific event trigger these issues?
---Bought at 13k. Always been the same. TCU update relearn helped a LITTLE bit...but got "bad" again over time. (not that bad).
6. What solutions have you tried so far, and did it improve?
---None
7. Mileage now 30k.

Personally, I find the transmission works well for aggressive driving. Especially in manual mode. But when driving gently, it gets confused, overshifts, and BY FAR the most annoying...drives me INSANE....is when in manual mode, when the car comes to a stop and shifts into first gear, it's ALWAYS a hard shift. Uncomfortable. People ask "Is it OK?" I've actually had to adjust my driving and put it in D when I know I am coming to a stop, and then accelerate back out in Manual mode. It's annoying AF, but I've gotten used to it, and it's part of my driving now.

As far as really hard and problematic shifts, I've only experienced it twice...and both times it was when paddle shifting, but ALSO keeping it in "D" mode. I would recommend to anyone with these cars if you want to shift manually, put it in Manual, because if you happen to paddle shift at "that moment" when Drive is doing it's own shift, you might surprise yourself with an uncomfortably hard hit.

I'm thinking about doing a level 10 tranny like Russ did (with the TT M56). He said it increased driveability. Also, supposedly, though I am UpRev tuned, now HP Tuners will support some of our M56's....and they DO allow for Transmission tuning also....????

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Re: Transmission Issues - slipping, slamming, mis-shifting

Postby Mickey917 » Sun Jul 18, 2021 12:47 pm

Sorry this is an old post but…

1. Do you feel like your transmission behaves funny, especially in city driving?

Transmission is working perfectly, except with 4 to 5 gear change that makes a little flare in automatic (about 250/500 rpm). It happens only when I drive it with few pressure on the gas pedal. When you hit hard it shift with no flare/slipping on that gear. In manual it is less noticeable (mostly not noticeable).

2. What year is your car?

2012

3. Is it a V8 or V6?

V6 Hybrid : I think that is why my post is important. I read a lot about people saying it may be the torque converter lock up doing the flare/slipping. Note that there is no torque converter on the M35h and that is the same issue that other people are facing !

4. RWD or AWD

RWD

5. Are you the original owner? Has it always behaved like this or did a specific event trigger these issues?

2nd owner. Always drive like this but as it is not very annoying it did not catch your attention every day.

6. What solutions have you tried so far, and did it improve?

Ecu reset procedure. It did nothing.
I also had a recall for the transmission/hybrid module update but it changed nothing (that is a 2016 recall applied in 2021 so I know it will do nothing on that point…)


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