Automatic 2-1 rough downshifting
 

I have the 7AT, and when i slow down at a stop sign or stop light, the transmission will shift from 2nd to 1st and the entire car will jerk like when you downshift a manual without syncro-rev matching. Has anyone else with the 7AT noticed this???? Will this go away after i put some miles on it? i have about 1000 miles already. Any help or advice would be great, i am planning on contacting the dealer about it, but i wanted to hear from anyone else on the forum who might know something that i don't.

THANKS!

I have a 6MT so I can't comment specifically. However, perhaps I can start the discussion and be of some help.

First, this is occurring on an automatic downshift performed by the car? ie, you're not shifting from 2 to 1 on your own? If YOU were doing the shift, I'd tell you it's unnecessary to downshift from 2 to 1 while the car is still moving...just shift to 1st once stopped.

Second, you might be able to circumvent this by shifting to neutral before coming to a complete stop, much as you do in a manual transmission. I haven't driven the 7AT in the 370Z, but many paddleshifters go to neutral with a 'double' paddle pull (ie both at the same time). If you did this when coming to a stop, it may avoid the issue.

The most help will of course come from those who have the 7AT and I'm sure you're waiting for their input...

Well, I can reassure you that your car isn't broken. My 7AT does it as well, and a few others have commented on the same. It's "normal".

That said, you can alleviate this by changing your behavior. Leaving it in D instead of M when coming down to a light helps, as does flipping it into neutral. You generally only notice it on slow deccels (like coming down to a light in heavy traffic), you'll never notice a problem when you're driving this car the way it wants to be driven (why on earth would you want to bring a Z to a complete stop? that's no fun!). Save M-mode for when you're really driving, and use D-mode in traffic. Your transmission, your gas mileage, and your passengers who no longer have to endure the 2-1 downshift jerk will thank you :)

I have the 7AT as well, and I dont seem to have this issue. Are you letting the car downshift itself, or are you downshifting?

He's talking about when you leave the shifter flipped to the left in "Manual" mode and come down to a stop very slowly, like at a traffic light. You start in a higher gear, and the car downshifts for you (very late, and very jerky by the time it gets down to the 2-1 shift). It's pretty noticeable.

Hrm, I hadn't noticed that, but I have a habit of just putting it back over into D when coming to a stop. I'll try it out on lunch!

You can shift into neutral in manual mode with the double paddle pull? Wow! Can anyone confirm this?

Oh wait, I have an auto. I'll check it out tonight...can't wait!

New license plate idea: MY F355

I just drove home and had an F355 in front of me. It was driven by a woman and I sucked her doors off as I passed her getting onto the highway :happydance:

I just checked, and there is no way to shift into neutral when in manual mode on the 370Z auto transmission.

If I am incorrect, please let me know...

As for the F355, I know it's almost behind the times performance-wise (and definitely in reliability and maintenance), but it's about the looks, sound, and history of the marque and car for me...

No, you can't. I really wish there was an easier way to access neutral in the 7AT while in M-mode, but there isn't. When I referenced shifting to neutral earlier, that means pushing the shift lever to the right (back into D), and then forward a notch into N.

I'm talking about dull "D" mode not manual mode. it downshifts really rough automatically.

when i am on drive mode i don't have any jerking on 2nd to 1st. only on M mode.

The high-end sportscars allow the double-pull neutral. Last time I saw it in person was an Astin Martin Vanquish.

< another AT owner who has experienced the "stoplight jerk"
It's enough to where I avoid the paddles unless I'm doing "spirited driving"

thats why you get maual lol jk idk contact your dealer

This is going to be a very subjective thing, which is why we get conflicting reports about people feeling it or not, and whether they feel it only in M or only in D, etc. Aside from varying sensitivities in general, it depends greatly on the speed curve you're decelerating at with the brakes (or just coasting down at), and the force you're applying with the brakes at the time of the downshift.

If you get your speed down well in advance of a light (like you're trying to roll and wait for it go green and never stop, for instance), and then get off the brakes around 20mph and just let it coast all the way down from there to the 2-1 shiftpoint on its own in M-mode, you'll feel it for sure.

I had the same exact problem with 7AT on "D" mode. It was actually pretty bad at first(first couple hundred miles,) bad enough so that I actually took it to two different Nissan service stations. Both of them told me that it's quite normal since the Z has such an aggressive transmission and it tends to do that coming to a stoplight at low gears. Anyways I don't know if I got used to it or if the transmission got better but it's lot less noticeable now at 3k+ miles.

Thanks Mola, good to know it may get better.

Mine has been pretty variable. Sometimes I don't notice it for a day or two, then I get a really hard hit of this the next day. I don't think it's the car getting better, I think it's that I'm adapting my driving to avoid it more.

I'll keep my fingers crossed. I'm kind of regretting not getting the manual, but I remembered how much I hated the stick in traffic, so I went with something different.

Yeah it's a tough call. There are a lot of times I wish I had the stick instead of the 7AT. But on the other hand, flipping to D in traffic is convenient, and this is a daily-driver in a pretty congested city (not that I actually commute to work, but still). Being able to let a friend or girlfriend drive the car home when you've had a bit to drink is handy too.

I've been to houston many times (Family lives in sugarland), and I wouldn't want a stick there. We have bad traffic too, but it might just be worse there.

Maybe, I've always had the worst traffic with accidents on roads trying to get back into Houston. Then again, the first time I was in the state, 5 minutes after leaving the airport there was a bumper damage crash at speed. Everyone kept driving. My dad said that was why I was going to be costing him 2k a year in this state :rolleyes:

I'm going to assume that the 2-1 downshift is rough because of the ratios. 1st is a 'pull away gear' that a manual user never downshifts into (street driving) because the ratio is really high. It's designed to get the car moving from a standstill, so the ratio is huge to get the torque to the stopped wheels.

The shift may be more noticeable because the Z is a 7 speed, and so it's relying less on the viscous and instead on making the shift to get the torque curves lined up than say a 4 speed. Then again, our hauler Commander really had some rough shifts at altitude from 4th to 3rd, followed by a very depressingly high rev as it weezed over the mountains.

I think that use will let you know how the computer thinks to try and avoid or mitigate the shift shock with time.

I live in Chicago with my 6MT. Our traffic can be horrendous, but I've made lemonade from lemons...bad traffic makes me get off on the back roads and gives me more time to drive home, enjoy the car, and zip through corners, turns, lights, etc etc.

Great suggestion :tup:

I've gone manual, and any 'fun' car will be manual, daily driver or not.

"Misery loves Company" It actually might be a characteristic of the car. I have about 16,000 miles on it and the jerk is still there. I actually remembered that first jerk coming out of the dealership's parking lot. I was hoping that with a little wear and tear, this issue would eventually disappear. I know some say that they don't experience this jerk and others do. As WSTAR mentions, I do feel the jerk between 2nd & 1st mainly when I do slow decelererations, but if I pound on the brake, the jerking pretty much becomes non-existent. The thing that somewhat bugs me is that it doesn't always happen. Shifting D to M makes this jerk even more prominent, so I end up just upshifting with M and then I switch it to D for auto-downshifting. I actually flipped my first 370. God rest her soul :( http://www.mervlin.com/pictures/my-accident/4480974 She also had this downshift jerk issue between 1&2. Well anyway, thanks to Insurance and knowing that the safety features work well, I just had to get another one. This car is like a drug. To be honest, I think these cars were made to be driven hard. A very good buy for the specs and the price. I just hope these jerking issues we are experiencing though doesn't force us to replace our transmissions every few years. (fingers crossed)

When the car is coasting to a stop and I'm still in second I ease off the brake and downshift into first. Downshift Revmatch takes care of the rest, then I reapply the brake. Smooth stops every time! What ever you do don't downshift as you depress the brake, the car WILL lurch forward when it shifts and if you're to close to a car already it'll ruin your day.

:iagree: I noticed the same thing - for whatever reason, on the rare occasion when the car was new and would downshift from 2nd to 1st (and I'm talking "D" or "M" mode guys - it doesn't matter, since the car automatically downshifts when it needs to, even in M mode) it would really jerk. I've got a little over 10K miles on it now, you still notice it but not that much.

BTW, the jerk is normal. Try downshifting (at low speed, of course) a manual from 2nd to 1st and see what happens - unless you're barely moving you'll feel a jerk and hear the engine rev.

In my 7AT, like others have stated, only in M mode do i notice the sudden jerk. Its not that bad, but it is noticeable compared to a stop in D mode.

now i just pull the ebrake when in M mode.

kidding. kidding.

I don't drive in D very much, but I never have a jerk stopping. I don't think I see it downshift to 1 until I'm stopped, though?

OTOH, in M mode I notice a jerk more from 4 to 3 or may be 3 to 2, not 2 to 1.

I don't like braking late in traffic, but it makes coasting down difficult to do smoothly. I wish the SRM worked on the automatic down shifts as well to help smooth that out.

This is normal. The tranny in my AT G does this and its annoying.. I have confirmed this with other people in the G world..

You should see what happens when you're rolling around 5 mph in 2nd then tap it into first lol. When I do that some electronic module thing starts going off and makes a "t-rrrrr" zipping sound for a split second then there is a plusing sound.. This all happens very quick but all normal.

Edit: Just to be clear. Yes my car has a violent jerky shaky down shift in "D" coming from 2-1 when going slow.. The triptronic thing is just as bad. Normal.

Mine does this sometimes in D

It's normal for some jerkiness while in M mode. The "auto" downshift in M is at a low RPM as others have mentioned. It's not normal to jerk in pure D mode however.

I ran some parking lot tests in my car coasting at 15MPH down to 0 (level and up a slight hill), and the car did downshift before stopping, at a very low speed. There was no jerkiness in M or D mode going from 2 to 1.

The sport brakes are a little grabby, and I have never noticed the downshift even when barely using the brakes.

My car has 18,000 miles but I am the second owner.

Did you guys notice the last post on this thread was 4/15/2009 and, all of a sudden, goes to today? Kinda odd how 1 1/2 years go by and the thread continues right where it left off.

It is what happens when good users search before opening new topics :D

Normal. Probably either something that could be smoother in the rev matching logic or something due to the physical actuation of going from lock-up to fluid coupling from 2nd to 1st.

Don't really like this transmission...
 

I used to owe a 350z automatic with manual option, and that was the best I have owned so far. I currently own a 370z with similar transmission and I have experienced rough shifting when upshifting or downshifting. Though I don't usually shift down to 2 or 1. This is quite disappointing since I love nissan products. I believe that they should have limited their gears to 6 not 7 for automatics, but I can see why at this time they didn't - lower rpm while cruising.

Mine does that too only in M mode. Had chance to took my car to the dealer last year, but the tech told me not to using M mode...:shakes head::icon14:
Now I have about 24000 miles on it but the jerk is still there but not that bad though. Maybe Im getting used to.:driving:

The tech's "solution" was to tell you to not use manual mode? :icon14: You shoulda' told the tech to :gtfo2:...