09' 7AT Rattle/Grind noise 1st to 2nd gear. Please help.

Lethal1

There is what seems to be a mechanical/metallic rattle coming from the front end almost like it’s coming from under the hood. This issue is very intermittent, and only happens when going from 1st to 2nd gear starting from a complete stop. Also, it only happens when I barely give it gas. Kind of like when I am driving very conservatively (Babying the car). If I get on the throttle even moderately it doesn’t happen, or hasn’t happened yet. When I first noticed this issue it was just a rattle noise with no feel of lost power. Now it seems to be a bit louder (at times) and sometimes I can tell there is loss of power (Like a possible gear slip).

In researching this issue I was starting to think it was the VDC that was causing it. However, I ran the car for about a week with the VDC off and I was able to reproduce the issue. I have taken the car to the Nissan Dealership twice for this, and they have had the car for several days at a time. They said that they cannot reproduce the issue. The car has 38K mi, all maintenance is up to date and done by Nissan. Also, the VDC off and slip indicator have come on at the same time twice with no action from the driver. When this happened those two lights will stay illuminated until the car is powered off and back on.

Has anyone else had this issue or do you know of a better way to pinpoint what's causing this? I purchased an extended warranty from Nissan when I bought the car back in January (31K mi). I really would like to have some more ammo when I bring it back to Nissan. I have attached an audio clip of the noise for reference. The noise is about 5-6 seconds into the clip.

Thanks,

P.S. Sorry the post was so long...

Attached Files

09 370z 7AT Grind Noise.zip (91.4 KB, 56 views)

fuct

I first wanted to reply with "thats just our noisy clutch" but there def is a rattle that doesnt sound clutch related. almost like a loose bracket or something in the engine bay.

NickTurnon

Had the same issue- Actually went away after awhile.

I feel like I drove it hard enough to fix itself...? I took it to dealer and even recorded the sound.

Lethal1

Thanks Guys. I guess I just need to quit worrying so much and just dirve the thing. I appreciate your replies...

NickTurnon

Is it still grinding?

Wonder why mine went away..

Lethal1

Yeah it's still grinding from time to time... Not sure why yours went away. How many miles do you have on your Z?

CrunchyCajun

Mine did the same thing.

Two weeks ago it stalled at a light . Felt like a manual transmission stalling when you fail a launch. The car made more noise on restart, which improved, but started making a noise in drive at idle and was not smooth.

Nissan replacing transmission now with 51k, warranty. Car has been mostly highway driven and not abused.

NickTurnon

What did you say to them? I still feel my grind every once in awhile but I have a different transmission than you...

CrunchyCajun

Not much, they could hear the noise. Nissan had them try a bunch of things, then told them to replace it after 2 days. Since the 7A is sealed, there is not much else they could do.

Have to wonder how complicated the thing is if they don't make it serviceable.

nismochiq

I am actually having the same issue right now, my car stalls at the light, the battery and the check engine light comes on, then a smell of gas in the car. what I recently started noticing was that when i downshift i am having the same issue, time to go to nissan tomorrow.

__________________

CrunchyCajun

I have had it back for 5 days. In that time I have put on 420 miles in a mix of city/highway (mostly highway). Transmission feels much firmer and tight than original ever did.

The MPG is up. I reset the MPG gauge monthly. From month 1 it would settle at 21.5. During the month before the transmission went, I noted that the MPG dropped about 3/10 ths, so I reset early and it leveled at 20.9 MPG, a big drop. With the new transmission, it has settled at 24 MPG. Same driving.

Can only speculate that the original transmission had some slip from the beginning and/or they have improved the 7A since 09'.

NickTurnon

I am happy to say that my Z has been running perfectly. Havent heard the grind in awhile. I still have 40k under warranty so I guess I have time for the problem to occur again.

Kind of hoping it will come back because i spent a whole $1400 on a service package that my finance planner said would cover my oil changes and other wear and tear items. So i want to at least get something out of it before 100k.

Im glad your tranny is better Crunchy

Lethal1

Hey Guys,

Just an update. The rattle has remained and I have just been dealing with it for the past year. I have since moved and decided to mention it to my new Nissan Service dept. I sent them the audio clip and they think it is spark knock. From what I have read this seems to be pretty harmful to the engine. Anyone familiar with Spark Knock. Any suggestions on a fix. The new Nissan dealership said I should have them do a fule system cleaning to remove carbon buildup. I currently have 57k but remember my car has done this since 30k when I bought it.

NickTurnon

Post a video so we can hear what your grind sounds like.

From your description, its nothing like the sound of mine. The grind that came from my Z was almost as if a stick was stick under the car and dragging. I believe it was part of the heat shield on the cats or another piece under the car that the metal was bent slightly and vibrating at certain frequencies..

Go buy a bottle of seafoam from WALMART. Watch my DIY, and try that out.

Why did you 27k miles to do something about it?

__________________
2009 Brilliant Silver BASE 7AT | TEIN S-Tech Springs | K&N Drop Ins & z1 Maf Tubes | AAM S-Line Short Tails | 5% Tint | 20MM Spacers | Sport Spoiler NickTurnon's 370z Build