This is somewhat of a bombshell (to me at least). BIG thank you to Allenzi35 for digging this up - we both put in a lot of time (mostly on our own, but with some collaboration) to identify the root cause of this problem. Apparently there are a number of 06-07 5ATs with defective valve bodies - this is what causes the mysterious violent shaking around 40 MPH (while cruising at low RPM or going over bumps). Infiniti has finally admitted that the problem exists...

 

Whoa..thanks. I was just going to pull my VB this weekend, maybe I'll delay that until I get my dealer to look at it.

 

Wow!!!!!!!! I just got my tranny replaced like two days ago under warranty !!! I thought I had bent my flywheel racing one night and bought a new flywheel but still had the vibration after the replace ! After the new tranny its like hot butter to drive . Same problem I had . At an idle at 1800 rpm's there was a serious vibration . It would go away the higher the rpms went up !!! You two are the Sh*t for putting this info up !! My car is like new now !!

 

yeah, appearantly this came out AFTER they fixed my car (by only reprogramming the TCM with new software, no parts replaced) and my car has not done that shudder since but it always acts like it wants to. I still notice weirdness with the tranny so I think im going to take it back and tell them that I want this TSB done since I had the original problem and overall still feel like something is just not with the tranny.

 

Before Allenzi found the TSB, we were thinking that it involved the TCM. The few dealerships that had realized there was a problem had been focusing on software. I guess it's understandable why Infiniti took so long to admit a problem, this is gonna be very EXPENSIVE if there are a lot of us.

 

only for 06-07 5AT? They have diff VB than previous gen?

 

Looks like it's only for the 06s and 07s. If I had to guess (and this is just speculation), I bet someone signed up a cheaper manufacturer for one of the components. Also known as outsourcing to China! The VBs probably have lead contamination.

 

good find!

 

so should i let the dealer take a look at my valve body? i was planning on installing the 5/16th isothermal spacer but i guess i should let them look at this

 

I wouldn't worry about a spacer, they're gonna have a really hard time blaming that for valve body problems, especially if you have a printout of the TSB

The VB issue is so dramatic, you'll know if you have it. The TSB got it dead on, it almost always happens at 40 MPH (+/- 1 MPH or so). The car starts shaking so violently, it could throw a drink out of the cup holder if you don't take some kind of action (i.e. hit the gas, brake, switch to manual mode, etc.). It shakes for a good 5-7 seconds, maybe longer if you don't take corrective action. The shifter will also vibrate back and forth (you can see it moving).

I think it took about 5-6 months for the problem to surface with my car. It was somewhat subtle when it started, the vibrations were pretty weak, and the frequency was only about once per week at most. But within 3-4 weeks of the onset, it was happening on almost a daily basis, and the vibrations were much stronger. Now it happens every day, almost every single drive. Once the car reaches operating temperature and the TCM reduces line pressure because the fluid has warmed up,

EDIT: the only thing (in my opinion) that you would definitely NOT want to do is a valve body upgrade, because you're basically paying $1000+ to have a defective part strengthened. Other than that, it's a factory defect, Infiniti doesn't have much wiggle room, warranty-wise. Hell, my car is completely bastardized and I guarantee there's a 99.999% chance that I'll get my VB replaced under warranty.

 

While surfing the G35 Forums I came accross this Thread. For what it's worth: I had a 3.5 SL Altima (leased) was traded in at end of the lease in Oct 2007. That car has FWD. It would experience a very similar shudder/ vibration at low cruising speeds 30-40MPH, most notably while in stop and go traffic (I'm in the NY area, so there's plenty of THAT). If you "floored it", I wouldn't feel the shudder, it was only at the lower cruising speeds which eventually, after 3 attempts at the Nissan dealer, was finally admitted by their mechanic. The replaced the same part referred here under Warranty : the Tranny control Valve assembly. After the replacement, It was better but NOT fully rectified. My personal mechanic told me that it was the Torque Converter that's what should also have been replaced, in his opinion, that was causing the "shudder". Got so tired of bringing the car back to the dealer for testing and so on, I knew it was leased, so I lived with it. I guess I should note that this problem was detected pretty early after the delivery of the car, but became progressively worse with added mileage.

 

On my 06 5at i get a violent shaking at about 30mph going up a hill. That is the only time it happens and it is so intermitant. It sound slike this same shaking bacause when it happens it throws things around in the car. What do you think?

 

Yep, that would be it.

Take it to the dealership and bring a printout of the TSB, they won't have any excuses. If you aren't heavily modified they should be able to scan for it.

 

I think my 03 has a valve body issue. The shifts are fvcked up and i don't think it is the transmission. Shifts are starting to SLOW way down during normal conditions and under hard acceleration it shifts so fast and hard the car jerks...

-Sean

 

When we [06-07 guys] first starting looking into the cause of this, we dug up some really old posts detailing the exact same problem. So it's entirely possible that it spans a much wider range, but Infiniti only admitted it for the 06-07s.

Here's a post from 04 - eerily similar symptoms!

https://g35driver.com/forums/showthr...ission+problem