i've had this problem since 2003.. when my car was new..
took it to the dealer twice.. they said it's normal.. software issue.. funny how it still exists on the 06 models.. that sux..

 

Allen,

Is there a modest hill in the area? Just take the service guy out and show him. Let us know whether that works.

Bern

 

Find a hill and try to go up in high gear 4 or 5. It sounds like a bad torque converter to me but the point of this is being able to replicate the problem when the dealer is checking it out.

 

I just got my car back from the dealer. They reproduced the problem and replaced valve body under warranty.

 

i had the same experience a few months back with my 06. first time it happened, i thought i threw a wheel weight and the balance was off. i let off the accelerator and all went back to normal. went to the dealer after it happened a third time and they replaced the vb as well. the new vb increased line pressure which helped some of the soft shifting in both drive and manual mode. it is no where an aftermarket vb job but much better than it was. make sure they used the correct atf and that they filled it correctly.

 

I now wonder if this it what I experience every morning, I assumed it was a tire issue, but I leave my road and head up a slight incline in a 50MPH zone, because the car is cold I ***** foot it and yes just about shakes me out of the car!!! I have noticed it at other times but this is very interesting. 2 dealers both told me they cannot replicate!!!!!! My 14 month old 06 now has 54k on it, I drive so much I can hardly getto the dealer with my issues before the warranty is done. A a side note I run 87 octane and although someone said if you can afford an infiniti you should by premium, I would say I burn so much gas at highway speeds that would be wasteful. Unless you are on the hammer all of the time, predetination is a non-issue!

 

This TSB might be related...

This TSB says my car is not affected, however my X does shudder in auto mode at exactly 40 mph under light acceleration. (it does not in manual mode)


APPLIED DATE: Built before May 25, 2007
Classification:AT07-003
Reference: ITB07-030
Date: August 16, 2007


SHUDDER AT 40 MPH


APPLIED VEHICLES: 2006 G35 Sedan (V35) 2WD only

2006 – 2007 G35 Coupe (CV35)

APPLIED VINs: 2006 G35 Sedan and Coupe, all VINs

2007 G35 Coupe built before JNKCV54E(*)7M 910237



IF YOU CONFIRM

The vehicle has a shudder when the transmission is at operating temperature and the torque converter is:

• Engaging lock-up in 5th gear (light acceleration at 40 mph)

• Releasing the lock-up in 5th gear (coasting at about 40 mph)


NOTE: CONSULT-II (2006 models) or CONSULT-III (2007 models) can be used to confirm
transmission gear position and lock-up condition.


ACTION

Replace the transmission valve body (control valve assembly).

• For replacement information, refer to the Service Manual > Transaxle and Transmission (TM) > 5AT >
On Vehicle Repair > Control Valve Assembly.

• Use the new control valve assembly listed in the Parts Information table.

 

Its not engine pinging that most people in this thread are talking about I think.

You can run lower octane (non premium) gas, your car will adjust the timing so that it will not ping/knock.

 

Really? Never experienced this or hears about it.

There has been a LOT of talk of a 2-3 shift shudder under acceleration. I get it. The only time I didn't get it was for the first 500 miles after tranny flushes... Also never get it in manumatic mode.

 

Sorry to drag up an old thread but I am experiencing the same problem. Shuddering on initial acceleration under 40mph. Does it everyday, all day, I have an appointment for this coming Monday morning. I have 12k on the dial, hope this is a simple fix. Anyone else with second gen having this issue?

 

Have you checked the trans oil level?

 

I haven't, I don't even know where the dipstick is! My monkey wrenching days are over, no more modding, no more tinckering. So I haven't even taken a look at the tranny oil level. I figured the dealer will figure it out. I hope it isn't a big deal. I went through 3 trannies on my Acura TL-S, I hope I don't have the same deal with this car.

 

i have heard of the tl transmission epidemic. good luck when you take it in and post an update if you get a chance.

 

I will definitely post what the stealership says. I hope its not "can't duplicate the problem"

 

I'd be interested in knowing if a tranny fluid level check is possible to do yourself. I couldn't find anything in the manual.