7AT Problem?
 

I purchased my '12 Z almost two months ago and ever since the first day I purchased the car, whenever I brake hard I feel a "thump" in the transmission as my speed decreases. I did a search and found that some 7AT have hard 3rd-2nd shifting and/or 2nd to 1st. Is this what I'm experiencing? If I brake softly then it doesn't do it. Its as if the transmission mounts are loose or something. Please help

Ask the dealer, it's under warranty.

Mine does this occasionally, computers fuggs up and downshifts to fast.

The problem is that mine does it every time unless I brake slowly. If it were to do it every once in a while then I can live with it but not every time. Can anyone else that has a 7AT please tell me if this is normal. Thanks!

Sounds like ABS. How hard are you braking? Is it sport pkg or regular?

Slightly clunky downshifting into lower gears on decel is normal... mine does that quite a bit, especially after manually operating the gears (the ECU learns your shift patterns, and "replays" them in regular auto mode.)

Unless you are hearing an audible "thump" or it's tooth rattlingly harsh, it's probably normal.

Still, if unsure, no harm in having the dealer check it out -- warranty!

I have the sport pkg but I have never manually shifted. Maybe manually shifting for a while will help the ecu? I don't really hear any noise just feel the car jerk forward as I brake down to about 20-15mph. But like I said only when braking hard...don't feel it while braking really slowly.

I mean if you are going to brake hard. The car is going to lean a little. As far as the sound. When a car is brand new, sometimes the brakes are a little noisy as they need to break in as well. The noises could come from the pads & rotors making contact when braking hard or the ABS? Your descriptions are not very good so its really hard to understand what you mean. But if I had to guess? Its just break in sounds from you braking too hard. Over time the brakes will smoothen out.

Sorry guys if I'm not explaining myself correctly. I believe jordo! Has it right its clunky downshifting. Its coming from the transmission not the brakes 100% sure. I'm not braking extremely hard either since the car only has 800 miles. I'm just frustrated because I just bought a $30,000 car and it feels like it has bad engine or transmission mounts. Its not noises I hear its a jerk forward.

I have the same "problem" It took me a while to figure it out. If you want to visually see what I am talking about, whenever you are coming to a stop shift over to manual mode and watch the gear number light. The little thump you feel is when you are coming to a stop and the car shifts from second to first. A good bit of times, it is a pretty good jerk. I believe, but not for sure, that the connection from first gear to second gear is different than the connections from 2-7. That is why I just ignore it and try to not let it bother me anymore.

Mine does this also once in a while it kind of bangs downshifting to 3-2 but mostly from 2-1.

I have the same situation. Sometimes the ecu is faster to the down shift in manual mode then I am so it feels like we had a split second disagreement but the ecu wins every time. For me I found slowing earlier and smoothing out the distance to stop in lower gears helps.

I have to say I kinda love the feeling it reminds me I am not in a sedan :)

Thanks jpritche you're absolutely right. I went out this morning and put it in manual mode while braking and the "jerk" that I feel is the shift from 2-1. I feel sooooo much better...thought something was wrong with my car. Thanks everybody for the input and help!

That's called DOWNSHIFT REV MATCH brother. What's being called a bump is your DRM is always active on manual mode. Its there so when you are on a highway, you can get an extremely fast throttle response when downshifting on the accelerator. When you downshift, say to a stop sign, you will feel the same thing. Under decel that would be called engine braking. There's nothing wrong with the car. If you don't want to feel it. Keep the car in D and only shift when you need to. Then let auto mode downshift for you.

:iagree:

That's the issue...it jerks when the car is in D shifting from 2nd to 1st. I never manually shift.

Right it does it in D also, I was just telling him to put it in manual mode that way he could physically see when it was happening.

I agree though, if you manually downshift, you will jerk a lot from the revs jumping up and the engine starting to brake hah.

Yes putting it in manual mode verified that it's normal.

I have had the same issue. It only happens in manual side and also only when the car is hot. I just down shift from 3rd to 2nd and problem solved. Plus I'm putting a lot more torque on the tranny than stock so I try to play it safe and do it for the car instead of waiting for it to down shift.

The only thing I can think of is if you are trying to make Andretti stops on the street? The ECU will use DRM to assist in engine braking as well as braking in order to give you more controlled and quicker stops. Sometimes my AT makes lil noises but I ignore most of them unless they cause some type of abnormal NVH. Nissans are loaded with tech that are always helping you do something. Occasionally you will hear them.

Also, I'm going to strongly go with you are also feeling ABS. That's it. Nothing more!!

I'm not feeling ABS. 100% sure of that. I'm not braking hard enough for ABS to kick in.

I agree. I feel the same thing. I have over 35k miles so far and everything is fine, so I just quit worrying. I still think it has to do with the difference in transmission connection in 1-2 gear. I believe it's "liquid"(could be wrong) and the rest are solid connections.

iv'e never had that problem. if you trust your dealer take it in for a check.
have someone ride with you... they will probably say it's normal but it's not....
but at the least you have it documented. if it does get serious.

I don't trust the dealer because like you said....they will say it's normal so I rather ask the more knowledgeable guys here. I didn't think this was normal but since others have claimed that their Z does the same I don't feel as worried anymore. Can others who have an automatic Z please chime in. Are you sure you don't feel any hard downshifts especially 2nd to 1st?

I wouldn't call it a hard down shift.
if your asking can I feel it than yes
but no way a hard shift. I would still
have it documented at the dealer to be safe

ive noticed it in the same range. rarely happens. usually on moderate braking (not hard braking). its just the car doing its thing, but if it concerns you, have them look into it for documentation's sake

I have a 2009 Base 7AT..Never had that problem. Sounds like it could be an issue with your Torque Converter.

I don't understand how some people can feel the hard downshifting and others can't :confused: Aren't they all the same car with same parts and assembled the same way?? I thought I read somewhere a while back that Infiniti G's had the same problem and there were various TSBs on this issue. Shouldn't Nissan have fixed this by now??

I have a 2012 and havent experienced any 'hard' downshifting in either auto or manual modes.... Unless i intend for it to torque hard.

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I just found this thread on here that shows others having the same issue.

http://www.the370z.com/nissan-370z-g...nshifting.html

And others don't :)

If I downshift manually, shifting two gears down from 4 to 2, it sometimes seems to be missing the DRM and I get a large lurch, but coasting down is always smooth from 3 to 1 - the only lurch I feel is from 4 to 3. I tried to pay attention today in D or M didn't matter.

Got this exact issue with my almost two months new 7AT too (car built in Feb 2012). very ignoring. I'm conditioned to get nervous everytime I came to a stop light now.

I feel as if my car is doing this less now than it did when I first purchased it. :icon17: It still does it just not at every stop anymore. I now have 1,300 miles so hopefully it completely goes away. I know how you feel about getting to a stop light...its very frustrating for this to happen to a new car. And the worst part about this is that it is a common problem for the AT.

I've experienced this for two years now. 3-2 and 2-1, and this is when letting the car downshift automatically, not doing a manual downshift. It happens when braking harder at the light, but I've also braked really soft to see if it would go away, and it still clunks pretty hard. I've felt varying degrees of the clunk from moderate to actually getting lurched forward and hearing a slight grind. It comes and goes, which to me is an indication that it's electronically induced from recent driving style, etc. I've noticed over time that after doing some harder driving and higher rev upshifts that it starts doing this. The only thing that seems to make it go away is taking it out of MM, which instantly makes it go away, and driving more conservative for a few days. Then going back to MM, it's completely gone for weeks at time. I would say each summer I've driven the car maybe 5000 mi and have experienced this about 8 times for a period of 2-3 days each occurrence over that time. I brought it up with the dealer, but was not experiencing it at that moment. They said to bring it over some time when it is occurring, but with my schedule, easier said than done. This year I had the worst clunk so far. I thought there would be parts left in the street. Would love to see how much metal is in the transmission fluid.

Yeah your right it comes and goes. It doesn't bother me anymore like it used to. I wish it wouldn't do this but I love the Z so much that I guess I have learned to deal with it.

Yeah me too. It also worries me that Nissan claims these transmissions are "maintenance free". Everytime I feel the clunk I wonder the same thing lol.