The following is a lengthy email I had sent to my father so that he could forward it to a contact of his that owns a local import repair facility. I apologize for the length, I was told to be as descriptive as possible for as accurate an email diagnosis as possible. Please read through and post any advice or assistance you might can offer. Thanks, and I know there are other threads about similar issues, so I know this might be redundant, but I decided to start a new one due to the length of mine so I didn't clog someone else's thread.


Approximately a month ago, my wife, Laura, was driving home from work and noticed that her car wasn't shifting into 5th gear and the check engine light came on. The codes that I cleared the following day were P1710 & P1716. After clearing the codes, I drove the car and noticed same issue. When put into manual mode, it would shift trough to 4th but not to 5th, then would default back to "D" instead of indicating the selected gear in manual mode.

After speaking with a friend of mine that is a technician at my local Nissan Dealership, and some other friends in the car business, I was recommended to go see Wayne at Wayne's Transmissions in Winston Salem. Great guy, by the way, but I'll get to that. He hooked up his monster scan tool into the port and started diagnosing. He found that a sensor on the valve body was showing a no output, or a reading on his scanner of "0" when it should of had some positive value while at idle. So after evidently describing this sensor incorrectly to my tech friend at Nissan, I got a $96 sensor in that didn't cure the issue, so I then had to eat that cost and bite the bullet on purchasing the valve body for a bargain price of $1,370. Confident that this was going to cure the problem, both by the advice of Wayne and my tech friend that even sent me bulletins from Infiniti about this very type of issue stating a few possibilities of symptoms.

Wayne replaced the valve body at the cost of another $300. I got a call a couple of days later with Wayne saying that the 5th gear problem was fixed, but maybe it was driven too long in limp mode and damaged 2nd gear because now it was skipping 2nd gear. After more inquisitions to a good friend with a Maxima of the same year and to my friend at Nissan, we determined that I needed to get the Transmission Control Module (TCM) reflashed with the Console II at Nissan. Wayne agreed that if I paid this current bill and the reflash didn't cure the problem, then he would deduct this amount from any further work that I needed. This still didn't fix the problem, and he suggested that the TCM needed to be replaced according to the test results from the Console II. Much to my dismay, I got all my options and decided to have a contact of Wayne's to come in for another $150 to test all electrical components on the car to ensure there was no break in a harness or anything like that, and his results were that it was NOT an electrical problem, it MUST be mechanical, so with an evergrowing bitter taste in my mouth, I authorized a $2,300 transmission rebuild minus the $300 I had already paid.

A few days go by and Wayne calls me and tells me that he took the transmission apart and inspected everything with a fine toothed comb, and he said he was eating his words. He said the inside of that transmission looks showroom new, and there's NOTHING wrong inside there. He said all seals and o-rings were in place, all tolerences were good, no overheating or scarring, no flakes, no damage of any kind to the trained eye of a transmission specialist. So he puts everything back together and only charged me $125 for the gaskets and fluids he used. He also didn't charge me the $150 for the electrical check of the car since by looking at the mechanical components, he determined that it MUST be electrical. Relieved, I spoke with my friend at Nissan and had him order the TCM which he had already suggested, to the tune of another $618. It came in, was installed and initialized...still slipping through 2nd & 3rd now. Now after speaking with Infiniti Tech line and another head technician he works with, he and Tech line are suggesting that I need to replace the transmission assembly.

To add insult to injury, he said that his parts department refused to send the part back because it wasn't ordered through the Service Department and since it had been installed on the vehicle. I spoke with the parts guy and gave him a diluted version of what I've made you read through, and he agreed to send it back and let Infiniti make the decision as to whether or not they would accept the return; luckily they did and I saved that money. Now after driving the car home from Nissan (only 2 miles away) it is MUCH MUCH worse now than it ever was before. When pulling away it pulls well through 1st, but slips as soon as it shifts to 2nd and leaves you with no power to the ground until the engine is nearly bounced off the rev limiter, and would then slip into possibly 3rd or 4th...not quite sure, but it took a good 45 seconds to move 200 yds up University Parkway trying to get it to fall into a gear after shifting from 1st. I had to turn on the hazard lights and was just contemplating coasting to the side and calling AAA when it fell into a gear and once at speed drove fine except for a kind of whining noise that wasn't there before all of this fiasco transpired.

I apologize for the lengthy description, but I wanted to give as much detail as possible to this issue because it has been such a nightmare for us. We still owe $7000 on the car plus a personal loan I had to get for another $2,500 for all the repairs and parts I was having to arrange, so we're in a situation to where we HAVE to get it repaired before we can sell it without losing more money, but we have to figure out what a transmission specialist and a manufacturer trained tech with help of manufacturer's tech line hasn't been able to figure out...unless the transmission specialist is wrong and it does need it. Then, my worry about proceeding with this, is that once a replacement is installed, that just as so many other times in this series of unfortunate events, I will be disappointed with news that it didn't fix it and it will turn out to be something else that someone THINKS it MIGHT be. I'm sure you can relate to my feelings of anguish here, so I don't mean to doubt anyone's ability, it's just been a terrible string of problems and non-fixes with this car. Did I mention that I encouraged Laura to lease an Acura that she found because she was gunshy when the transmission started giving her an issue. I only encouraged this because I was in stage 1 of the process when the part and labor were going to be $346; so now she's leased a nice new car and I've taken over $265 per month payments (which I haven't had since my current car, a 2000 Sentra 2.0, was paid off in 2006) and current parts and labor costs and an uncertain amount on the horizon. Thanks for any assistance that can be offered, it will be greatly appreciated.

 

Has the tech tested the transmission fluid pump? You replaced the valve body, maybe the fluid pressure is not up to task therefore causing slippage. Since clutches were checked when the transmission was rebuilt, its likely that the fluid pressure is not where its supposed to be. The valve body directs the fluid where its supposed to go when the car supposed to shift. If the valve body does not get enough pressure it will never make a proper shift causing slippage.

 

Thanks for the new idea, I have a new contact I'm trying at another local, but more highly recommended, transmission repair shop, so I will pass this possibility along and keep you posted on the results. Thanks for the reply!

 

I would also tell them to check the fluid pressure sensor and monitor the fluid pressure in general during idle. Im pretty sure Nissans Consult 3 can do it and there are specs in the shop manual stating what the pressure should be. When i was working on my 2nd car which was a mazda 626 with 4 speed auto, it jerked heavily during shifts. It turned out a bad fluid pressure sensor which read wrong pressure causing the valve body to receive much more pressure than it can handle and route. Mind you i had no check engine codes or over drive blinking during this problem. Replacing the sensor solved my problem although i had to rebuild the transmission because the pressure ruined the bearings between the clutch packs.

 

Are all your grounds in place? Engine to frame and frame to body. If the car is hunting grounds it will come up with ground wherever it might be and it will look to the tranny. loss of ground will make it shift funny or hard