is it the exact same unit on the AT+PP and the MT, or do they just also have the VLSD? from what i'm reading the VLSD is in the diff itself, and closed off from the diff fluid, so it could be that the AT+PP has a different Diff unit with the same VLSD in it.

or it could be totally unrelated to the Diff and this is just red herring.

i had like 8 different noises in my tranny this morning when i didn't have time to let it warm up for more than a minute or so. this car really doesn't like the cold. but there's gotta be something we can do to get this noise worked out.

anyone have a presence on a Z forum so we can get them on this too and get something figured out?

 

I too have noticed this noise with my 06mt. I do have a ztube with drop in filter. As far as transmission goes, I have a brand new clutch (2k miles) and recently it just started grinding occasionally when shifting into 2nd when shifting under 4k. I took it to the dealer immediately after the first few grinds and they said the car was fine. I'm going to take it a different infiniti dealer soon to have a 2nd look.

 

ok, so looking through infiniti-parts.com there doesn't seem to be a distinction between an auto diff and an manual dif, just an LSD dif and a non-LSD diff. so unless people know otherwise, it sounds like both AT+PP and MT have the same rear diff.

are there any dealers with a presence on this forums that could confirm part questions like this for us?

 

^ I believe the only thing that is different is the axle ratio. Yes the viscous fluid is sealed and separate from the diff fluid.

 

Just to make things more confusing, I had the noise for the first time this winter and I just had a diff and transmission service done at the dealer in April. Found a thread about the problem and that a specific dealer acknowledged it as bad synchros in the transmission and had mine replaced under warranty a month ago. Guess what, the noise is still there! I took it back and they replaced the transmission fluid and said I should allow the transmission time to break in and that maybe the noise would go away. Another guy who went to the same dealer said he got a new transmission and the noise is gone. I PM'd him and told him that I still had the noise and he acted like a bone head and said something like he heard the dealers had pawned his old one off on somebody else and it was real noisy. So anyway, the noise is still a joy to my ears. Yeah right.

 

^ ugh. so you're 100% positive you didn't have the noise until the fluid was replaced? you had the car for a winter before the service and never heard the noise? I'm just asking cause i've got a buddy who has had his car for a couple years now and didn't notice until i told him to drive for the first ten minutes with his radio off and listen. i wanna make sure it's not possible that this just went unnoticed before and you're just thinking it was related to the service because you noticed it first around then.

ok. I believe i'm going to make a call to my nissan dealer today to start getting the issue looked at, so i'll keep everyone in the loop here as i'm going as well. I figure i've only got a year left on my powertrain warranty, so if this is transmission-related i can get it addressed. which means that, since obviously no progress will be made when its warm, i've got about 2 months to get this puzzled out. hooray.

 

[QUOTE=maxuz;3829483]^ ugh. so you're 100% positive you didn't have the noise until the fluid was replaced? you had the car for a winter before the service and never heard the noise?

yes

 

Your Nissan dealer will not likely help you with Infiniti warranty unless you're referring to an Infiniti dealer.

G/L and keep us posted

There is no way you could not notice my noise. I've got about 16 months left on my PT warranty. My issue has been documented for 3.5 years.

 

^sort of what i'm afraid of. the closest infiniti dealer is like 3 hours away.

 

Does anybody subscribe to the theory that this could be a pilot bearing? Today, it was in the 20s and I let the car warm up for 15 minutes. The noise was not there and the transmission felt much better. To me, the transmission and internals including the fluid would not have warmed up enough to change what has been going on. Nothing is moving in there while the car is at rest. Additionally, I have noticed that when I first start the car, the RPMs dip considerably 200-300 RPM as soon as the clutch is engaged (pedal up). It's almost like the clutch or flywheel is cold and needs some time to loosen up. This RPM behavior has become more noticeable after the new transmission got installed, which may point to something else entirely. But my thinking is that the clutch and pilot bearing warmed up and the noise wasn't there. By the way, did anybody find this so called flap or vent? I really wish that was what it was, but it seems like a long shot. Also, what about the guy with the stethoscope on the differential? Any news on that front?

 

I haven't heard the pilot bearing theory but that would be rpm based wouldn't it?

I know I've seen the rpm drop when engaging the clutch while cold on several cars. I even had one that would immediately stall if you didn't give it 5 seconds when it was really cold. It's just the increased load bogging down a cold engine; I doubt it has anything to do with this.

 

Update: new transmission = noise gone!

 

^ how long have you had the new transmission in? how many miles? How many cold cycles has the car sat through without making the noise again next time you drove it?

any indication from the dealership or on the work order as to what tranny fluid they put in it?

 

^ how long have you had the new transmission in? Just picked the car up wednesday.

how many miles? I'm assuming you mean on the transmission. I probably have ~100 miles on the tranny and 57K on the car.

How many cold cycles has the car sat through without making the noise again next time you drove it? 3 so far

any indication from the dealership or on the work order as to what tranny fluid they put in it? No, but I asked them and the service rep said they put 75w-90 syn. He also said that the tranny came sealed up with fluid already inside. So that means I can't be sure that they know what visc the fluid actually is. I guess I just have to take his word.

 

Great news. Keep us posted for the next while please.

I'll PM you after you're sure it's solved to get your dealer info if you don't mind. I would like my dealer to make contact with yours to confirm issue and the solution.