Just to update everyone:

brought the car to a reputable tranny shop in MA. they checked it out and said something about the clutch packs being gone which is typically the result of the computer inside the tranny malfunctioning. the cost to repair is going to be in the $2500-$3800 area. He said he would be able to tell me more specifics tomorrow when he actually rips the thing open to see how much damage has been done and determine what he will have to replace.

Just out of curiousity i called the dealer to see how much they would charge to do the work and they said that they wouldnt replace the clutch packs or the computer, rather they would suggest installing a new tranny (go figure) which would cost in the neighborhood of $5000-$6000.

If i get more info from the transmission place ill update you guys

 

well, the transmission shop just called back and told me that the computer inside the tranny malfunctioned which caused low pressure on the clutch packs and ultimatly caused the clutch packs to burn out. I was given the following 2 options:

#1 Replace the damaged clutch packs, computer, and valve body inside the transmission for $3200. This came with a 1yr/12K mile warranty

#2 Replace the whole transmission with a completely (ceritifed?) rebuilt transmission for $3800. This came with a 3yr/36K mile warranty

I opted for option #2 as i plan to have this car for another 3 years and really like that warranty. The car should be ready by tomorrow night.

Man, what a to the wallet

 

How's the new tranny doing? I know it's only been a few days. I'm having this same problem and I really hope I don't need a new transmission. My car is still under warranty (06' 5MT coupe), so I'm taking it to the dealership tomorrow!

 

same exact problem here
i still can see that nobody has found the solution
please let me know if you found any solution for the problem because it is making me crazy...

 

i thought im gona be alone on this 1, 2008 G35 with 36K on it , car has always been driven hard , and i had to slow down in the past week due to tire issues , and thats when i noticed the issue , im sure its not clutches as they tend to slip under throttle and high temps , this happens with cold starts and low rpm's so for sure it has to do with transmission fluid and the TC , i parked the car at the dealership and will go to test it out first thing in the morning when its cold , will keep you posted

infiniti changes the whole gearbox under warranty here, fingers crossed !

 

I took my '04 g35 in because the tramsmission feels like it is slipping starting in park. The dealership shows transmission codes and said may need to replace valve body($1400). Does that sound right? I have 90,000 miles on the car.

 

I have that problem, but also another problem as well.

When i'm cruising in traffic (and in traffic only), at about 10-15 mph, and want to give it a little gas the rpms will go from 1k to 1.5k before the car actually starts moving. Any ideas?

 

Torque converter not locked up.

 

Thanks, but i'm not sure exactly what that means.

Also, i noticed it seems to be happening when i'm cruising downhill, and when i give it the tiniest bit of throttle, it seems like the engine is revving up to catch up to the speed the car is traveling, IF that makes sense.

Only notice this in heavy traffic stop and go

 

What tranny shop did you go to? I have to have some serious work done to mine....

 

Think of your torque converter as a clutch. Until it locks up your engine rpm can vary with load without any change in speed. Once locked up it will tend to change with speed. Sort of the difference between a clutch that slips and one that is fully engaged. If you torque converter stayed locked up it would stall your car when you came to a stop. This actually has been a problem with some older cars when torque converters were first designed to do so, I think some Chryslers had this issue when fuel economy first became a big issue.

Some cars lock up at a magic mph, others do the same but will kick out based on throttle position (I think most will do this now anyway), others will lock up based on current gear. For at least some Infinitis this has been stated as in 4th and 5th gear (note the quote below in regards to 3rd, 4th, and 5th gears). Considering the speed when you are in this speed range it may well be the non-issue many have reported with their cars stumbling at certain speeds, that is the transmission moved or is moving in between lockup and non-lockup torque converter modes. You can see some of this effect when using the manual shift mode.

From the 2007 FSM -

-----------
Lock up occurs at Closed throttle 31-36 mph, released 29-34 mph
Lock up occurs at 1/2 throttle 86-91 mph, released 65-70 mph

Also:

Slip Lock-up Control
• In the slip region, the torque converter clutch solenoid current is controlled with the TCM to put it into the
half-clutched state. This absorbs the engine torque fluctuation and lock-up operates from low speed.
This raises the fuel efficiency for 3rd, 4th and 5th gears at both low speed and when the accelerator has a
low degree of opening.
----------

 

Is this normal for this car? I have an 03 g35 coupe. I can't say for sure but i think i've only started to notice this happen in the last couple months. Could it be transmission slipping?

Also, don't know if this is related but recently i got a drain and fill, and my mechanic told me the AT fluid level was at least 1/2 a quart overfilled, and i've been driving with that for 20k miles.

please, need help solving this issue. thanks!!

 

Last week my tranny starting slipping in 5th gear. Going 45mph ~2k rpms on a flat road, gave it a slight increase in gas and the rpms increased, speed didn't. Ran several experiments and they were all the same, unless I slammed the gas so the car down shifted or manually shifted in to 4th gear.

Took it to the dealer and they said I need a new transmission. Luckily I bought an extended warranty and it is covered but WTF. I use to tease my wife about the quality of her Chrysler minivans but they have never had transmission failures and we keep them past 100k miles.

2003.0 5AT 89k miles

I was planning on keeping it until ~175k miles. Now I'm not sure. Why would the new one last 100k miles if the original one didn't?

 

Same problem that i am having 04/coupe 60K miles

 

Looks like I am not alone. Mine is a 2007 G35S at 56kmiles and I observe/reproduce this when accelerating steadily, about 25% load, when the AT shifts from 3-4.
The RPM drops about 200, goes back up 200, then drops to whatever the 4th should have at that speed.
Is there a TSB on this? How do I explain this to my service manager?
If there si something wrong with the TC or TCU, I would like to get that fixed before I am out of warranty. Any hints or help?
Thanks,
Adil