We've had this sedan a short while. I found the AT fill tube, removed the 10mm bolt, only to have a plug in my hand with no dipstick. I assume it fell down the tube and the end is on the pan floor. Is that possible?
The car has begun to rev when under slight load, usually in 5th. When in "sport driving mode" almost no issues. Dealership charged me over $100 to tell me I needed a transmission and a TCU (?).
It acts like it might be a little low on fluid,but I thought you guys might be familiar with the symptoms.
Thanks

 

Some of the 03 model G35's were given a plug and not a dipstick. As for your symptoms are there any lights on and how many miles do you have on it?

 

I drained a gallon of blackish fluid from the pan drain and refilled with 4qts of Matic S. Still slips in D 4th or 5th. MM is much better. I'll do another iteration or two to see if things improve. Pulled a P1716 code, trans speed sensor. I don't know how long it's been there. I cleared it and it hasn't returned. No check engine light now. I changed the TCM to no avail. Mr Transmission was no help at all, but his price was right.

 

By the way, I learned today that G35's with a build date before 08/02 did not have a dipstick.

 

i have a 03 G Sedan 137K on the clock and the trans slips in 4th and 5th and randomly at times but i have to drive around in tiptronic mode 1-3 gear to just get around and so i called Infiniti and my car was manufactured 06/02 and they said it would cost almost 3900.00 for a re manufactured transmission with a 800.00 dollar Core so around 3100.00 total without install i have searched internet to find a salvage yard that has one for sale with decent mileage but just find sites that have horrible reviews and seem sketchy as hell. i think i am gonna drive it and pray that is magically fixes its self. but in other words we are F-ed...

 

I am in my 3rd iteration of a trans pan drain and refill. The blackish fluid is slowly turning a dark purple. I will do this again, and possibly again, because I am starting to think that things are improving. We'll see. I wish I had researched more. I service all four of my cars and this one was designed for Mr. Nissan to see regularly. If anyone needs a TCM cheap, I have one.

 

ATF should be pink. Did you ask the dealer if he can specifically increase line pressure so you can get more life out of the transmission? It does sound like you may need a rebuild. I would not replace the transmission. Just get a rebuild kit (high performance if you want/need it) and get it done locally. Should be 1/2 the price of the dealership remanunfactured unit.

 

In my other cars it is red. Thanks for your help, but I think we are getting to where we need to be, one gallon at a time.

 

So how is your trans running now? I'm having the same problem but today it felt like my trans is gone.

 

Our G35 has not changed or improved.
I replaced the TCM to no avail and have gone through 5 iterations of fluid changes to no avail. We just drive it in Tiptronic and it does fine. Good luck.

 

I have a 03 g35 sedan (08/02) AT 145,000 miles and it started doing the same thing about a month ago. P1716 code. 5th gear is basically gone. Revs real high but very little acceleration. I also noticed that driving in tiptronic helps. I pop it in 4 and after reving consistently at 3-4000 rpm for about 3 secs, it goes into drive and I can't used tiptronic but works alot better but the problem is still noticable (doesn't go into 5 though). I don't think you should keep driving it though, it could possibly damage the tranny even more. After a 2 weeks of denial, I figured it's not worth spending 3 grand on a car worth only 7 (atleast in my case) so it's for sale.
If possible, I still would like to save $3000 in mods so do let us know if you know a solution.

 

Seems like you guys are running into a situation similar to mine. My 07 tranny started slipping about 3 months ago (Only has 40,000 miles). My check engine light came on but i figured it was because my o2 sensor wire ripped and a few days later, the car stopped turning on. Took it to a shop and they told me that the TCM wasn't sending out power; that it was in a lockout mode. From there, i sent it to a dealer in tamarac, and they told me the entire tranny needed to be replaced because the TCM was making the car believe it was in 1st gear. I can't wrap my head around why a new valve body/tcm can't just be installed? $1,500 with install is a lot different than buying a used tranny and having it installed. But yeah, to answer your initial question, I think your TCM is going haywire.

 

Our G35 has continued to be ok just in Tiptronic. In fact the TCM I bought for it that did not help is for sale. In fact, the G35 is for sale. But, who wants to buy it in this condition?
A local transmission shop just rebuilt by transmission for a 94 Cutlass and it cost $1300. He said he could rebuilt the G35 for $1500. I had been to 4 other shops and they were 2 to 500 more. So, it is a judgment call. Personally, I do not plan to visit another Infiniti dealer just to be insulted and lied to. Nor will I buy an Altima or any other Nissan vehicle. I am unworthy. My next car will have a cable connected from the gas pedal to the carburetor, again.