G37/370Z 7AT FAQ Mega-Thread
 

I'm putting together a FAQ for the 7AT because it is quite the topic of discussion for our cars and the 370Z. Regardless of your opinion of automatic transmissions, this thread is based solely on facts and questions surrounding the 7AT. I have pulled a lot of information from many sticky's, threads, and other forums into this one thread.

Q: My car seems to jerk while decelerating and at low speeds, and I have rev flare between upshifts like the transmission is slipping. Is this normal?

A: Yes this is normal, especially on early models. The 7AT on the G37/370Z (Nissan/infiniti JATCO JR710E) have a special torque converter that can cause odd behavior that don't happen the same way they would on a normal automatic transmission. Here is a quote by Nissan NA



Q: That sucks. How do I stop the harshness and rev flare?

A: The simple way that seems to remedy a lot of issues people experience is to have the dealership update the ECU/TCM with the latest TSB, ITB12-027d. Most have noticed marked improvements in harshness and reduced rev flare, while others also report that it tamed the transmission to be far less aggressive (lazier shifting).

Q: Will an aftermarket tune improve shifting?

A: In most cases, yes. Both EcuTek and Uprev can increase line pressure for the transmission, making shifts quicker and firmer. They can also tell the transmission when to shift in the rev range based on throttle position.

Q: I have an aftermarket tune, can I still get the TSB?

A: Yes, you can still get the TSB. BUT since they also flash the ECU along with the TCM, it will overwrite your current tune and change the ECU information, making it not possible to reflash your tune without getting a new tuning license from your tuner. For more information about how that would work, speak to your tuner. The easiest solution would be to get the TSB first, then the tune.

Q: What ways can I improve the 7AT?

A: There are a few ways (depending on how deep your pockets are) to improve the 7AT. Some are these solutions are helpful to those going forced induction (I'll discuss this later).
Listed below:

-A grounding kit is one way people have noticed drastic improvements to the 7AT. The theory behind it, is that improving the ground between key points in the engine bay improves signal to many components of the drivetrain and electronics in the vehicle. DIY and discussion is in this thread. In my opinion, I feel like this restores transmission performance lost over the miles and years, not necessarily improve it.

Note: Some have stated that there is a battery current sensor and bypassing that may throw off charging rates or cause battery issues.

EDIT: After performing this grounding kit, I started experiencing issues with knock. I went into it further here.


-An aftermarket tune can greatly improve the behavior and performance of your transmission.

-LEVEL 10 Transmission upgrade. Level 10 is located in Hamburg, NJ and for a pretty penny they will rebuild your transmission with upgraded torque converter and valve body. This will improve the 7AT to far more modern standards, giving it very fast shifts.

-GTM Stage 4 Upgrade. Similar to the LEVEL 10 upgrade. Video below.

Q: Nissan states the transmission doesn't need servicing, is this true?

A:
Short answer.
Maybe? Plenty of people have never serviced the 7AT and they are fine

Long answer.
While Nissan states that the transmission needs no servicing, many of user will disagree and would like to have the transmission fluid replaced. It is my personal opinion that it should be replaced, or at least checked, every 100k. Others recommend 70-75k, some even state as low as every 30k for aggressive maintenance schedule. Methods will be talked about next.

Edit: In a bulletin released by Nissan/Infiniti, the ATF Matic S fluid used in the 7AT does darken quickly, but this is not representative of how the fluid is actually wearing and lasts far past the point of darkening, according to them.

Q: I want to have my transmission fluid replaced, how do I get this done?

A: There are two methods to replacing the 7AT's fluid. Fluid change and fluid flush. Both processes are very specific to the 7AT (though similar to other transmissions. The 7AT uses Nissam Matic S fluid. There are other compatible fluids, but I would not recommend deviating from Matic S.

The fluid change is the safest and preferred way. The DIY and explaition of the process can be found here.

The flush is the most aggressive, most thorough way to do this. It is recommended you take your car to a Nissan/Infiniti Dealership to perform this process because it requires a machine and a couple "special" pieces of hardware.

Q: I'm going forced induction, how much abuse can this transmission take?

A: Though there is some debate, it seems like things start to break (or at least have drastically reduced life) around 400tq. I'd recommend getting the LEVEL 10 or GTM upgraded transmission if you are going for big power. LEVEL 10 states that the 7AT is particularly weak, specifically in the 3 highest gears and it is recommended that you get their "Bulletproof" package for additional toughness.

If anyone has more information, I will be adding more things as I get more information on the topic.

Is there any danger in upping the line pressure? Thinking about doing all these things.

Seems like a pretty standard thing to do for tunes from what I've seen. I'm sure there is very slight danger. Since the some engineer somewhere decided on the line pressure and designed with that in mind, but IMO the hardware involved can probably take the increased pressure just fine.

During my conversation with Level 10, they claimed the 7AT was weak, particularly the top three gears.

I hope to have them rebuild my valve body. Part and parcel of this is an UpRev tune which they can do. Fingers crossed it'll happen this fall.

Hmmmm. Good to know! I hope to have info like this start showing up in here.

Good write up and references for sure!


Adding to the conversation, the 7AT is fairly weak and will fail eventually with added power. Level 10 offers their "bulletproof" service that does the TC, VB, and clutch packs. I have this and it has been holding perfectly at around 600-650awhp and multiple track days and hard launches.


When getting the transmission worked on and tuned for line pressure be sure to double check the components and if they need to be reflashed as a whole to ensure that the ECU and TCM communicate properly. This caused me a headache burning through clutch packs in the transmission a handful of times.

I guess I should see if I have the latest TCU update. Sure don't want the dealer flashing over the UpRev changes.

Nice write up. I might look into grounding kit.

Great thing is it looks like used transmissions are dirt cheap on Ebay. $400-500. So you could buy a used one, have it rebuilt, and get it put in with minimal downtime. Definitely something I'm thinking about for next year.

Sticky for effort :D?

Definitely!
And worthy of plenty pushes of the "thanks" button! Well done, although I'd go 70k miles for ATF service.

Thanks!

I saw lots of discussion of at what mileage the service should be done, so I just gave my opinion since no one really knows lol.

Updated for more info.

For reference, I just performed the grounding kit.

I already have a tune, but I noticed some change. Downshifts on 3rd and 4th are lightning fast, but they were quick before. So there is minimal change there. Upshifting during medium throttle are a little smoother now. There is less lurching.

All in all, I think it's worth the $20 in supplies.

Do you recommend a kit or piecing together the wires on your own? Also my G has like 45K miles.... is it too early to worry about a flush? I wanna get the low hanging fruit first.

Definitely piece it together, it's easier than installing an air intake. Just a bit time consuming crimping and such.

As far as a flush. Now would be a good time if you are doing a full flush.

BE CAREFUL DOING A GROUNDING KIT. I DO NOT RECOMMEND BYPASSING THE CURRENT SENSOR. HERE IS WHY.

Nice catch!

Regarding the current sensor... what does the battery negative terminal currently connect to? I'd imagine it would have to be a chassis ground no? And yea it does look like it could take a much fatter cable.

Have there been any changes in the 7AT through the gens or models? I have a 2014 Q60S coupe.

I'm not sure, but I think up until 2015 they were the same.

L10 advice.
 

I have a stillen kit, uprev tune, and hi flow cats on a G37x with 7AT. ~ 400whp depending on the day.

I also have a transmission oil cooler. I talked with Pat at L10 a long time ago about transmission upgrades. His advice was:

1. Wait for the transmission to fail before sending it to him for bulletproofing. Doesn't cost more.

2. With oil cooler, and not increasing boost, transmission may not fail for a long time, or never.

3. I should send him the torque maps for my uprev tune and he could improve the transmission tuning, reducing the lag from hitting the paddle shifters and actual shifting.

That was 40,000 boosted miles ago. With the transmission cooler, I haven't noticed any degrading of performance.

I have drained and filled the transmission twice; which changes ~half the fluid. Once when I put in the cooler, and again a few months later when my WIX plastic inline magnetic filter exploded. Using Amsoil Sig. Series fuel efficient synthetic fluid, not Nismatic S. FYI, the 7AT pressure is much too high for a plastic filter. Use a welded metal or billet filter.
I use the same amsoil fluid in my supercharger. Amsoil says it is compatible with Nis S. After all, Nissan doesn't actually have a refinery making their precious fluids.
Haven't sent Pat my torque tables yet. Did a grounding kit and I am satisfied with the transmission at this point.

As for fluid changes, my personal feeling is they should be done every 30,000 miles or so; and never do a flush. The chances of f'ing something up with a flush are too great.

"Sealed" transmissions
 

Some manufacturers stopped putting in AT dipsticks and filler pipes, as well as service intervals, for the following reasons:

1. With newer transmissions and synthetic fluids, they are confident the vast majority of trans will outlast the warranty (barely) without service.

2. Incorrectly filling (overfill, wrong flluid) or flushing will increase warranty claims.

3. Filler pipes and dipsticks allow contaminant entry.

4. Customers like stuff that is maintainance free. They also like plastic engine covers so they are not offended by seeing actual engine parts.

Repair histories I've seen suggest under normal conditions, the transmission should last 100,000 miles with no service, then fail soon after.

If you are reading this, your car ain't experiencing normal conditions! A fluid drain and fill every 30,000 miles or so is cheap insurance, considering the expense and hassle of a repair.

If boosting, racing, or driving hard, I would put in a cooler and inline mag filter. Again, very cost effective compared to repair / replacement.

Why a magnetic filter? Most of your contaminates will be shredded clutch pack material.

Well that's good news for the cash strapped who want boost. Great.
I have read many times "Don't boost in 5,6,7 gears. The clutch packs are weak"
What exactly does that mean? That you can only shift into those gears below 3000rpm?
Is that what you have done to keep your auto from destroying itself?
It would be nice to know how you use your boost since you are one of the few that did not grenade the stock 7AT.
Thanks for the info.
Much appreciation for those who share this stuff!

Do you mean you are against flushes from a DIY perspective, or the concept as a whole? I would think that a flush would be beneficial here if you are using the machine to do. Straight fluid transfer, old to new. I've heard some stories about particulates being dislodged from the process and royally borking things up when it moves around in the system, but it's more stories than actual evidence. Curious to hear your thoughts, and thanks for chiming in with the information!

Hello Can I suggest a TMC Motorsport TCU Auto Flash
 

Hello, I have a G37 sedan and I have everything you can imagine for a N/A, except headers, turbo, or supercharge I have a VR Autoflash from the U.K. for about two years, it works but then it automatically resets and you have to reinstall and tune it when ever it happens. I have the old version a red obd2 that has been discontinued and vivid racing or agency power stop selling. With me researching a TCU flash, I found a few options and recently came a cross the black tool version now for 2018 from TMC sports.
I didn't want to purchase another one for my g37 but it was my wife's birthday this October and she owns a 2016 Mazda 6 and she loves how my car performance and enjoys taking it to work because it's fast when she needs to step on the gas compare to her Mazda 6. So I surprised her and spend about $5,000 including install of custom axle back exhaust, jbr racing sway bars, bilstein b8 front shocks and Koni yellow rear struts paired with vogttland springs, stoptech slotted brakes, megan racing front strut bar(extremely happy with it for this application, $65 on Amazon deal), mygenius tune, Injen CAI, pedal commander, and a auto transmission oil change
I had to list all this so that I can further explain my experience driving with this set up and it was very fast after with all this upgrades but what suck was the gearing of the transmission is horrible, slow as crap and it just didn't match up to the new upgrades the engine has now. Behold and guess what I purchase TMC Motorsport Automatic flash from the U.K. it was $400 shipped within a few days I order to the United states.
My first impression was like okay simple tool like mines but black that ones you install the tune is saved for ever, or until someone programs another tune or update thru the eco, you need to tune it again. It has unlimited tunes ones it marries your vin# and ecu.
ones I did the simple installation I followed all instructions to tune the transmission, after I drove it for 20 miles and maybe another five more in the morning. I didn't feel any change, so Inwss like oh crap it's not gonna work. So later that day I drove another 20 miles and after I felt like okay it's working a bit and got extremely happy.
The next day I warm up the car to drive a 50 mile roadtrip to fully test its capabilities. As soon as I stepped on the gas it was so much power unleash and the way it change gears was like on point for upshifts and downshifts instantaneously you can feel the difference from night and day you won't be disappointed. I love to drive my wife's car everywhere now it's fast compare to how it was before and it keeps up with a lot of brand new sport cars that are more powerful stock. I also want the transmission level 10, but until I have that, I will need a twin turbo and built motor setup to justify it. For now I'm going to wait for black Friday sale and purchase the tmcmotorsports Automatic Flash. : )

Late reply, but from what I've gathered reading on the 370 forums is: this means you don't romp on the gas at low RPMs while in 5-6-7. If you're cruising in any of the top three gears and need to make a maneuver, you downshift into 1-4 (whichever makes the most sense given your speed) and bring the RPMs up before going WOT. It's my understanding, that the sudden load put onto 5-6-7 is what causes them to give at low RPMs.

Again, this is just my interpretation of it and if someone else would like to add or correct this interpretation - please do.

Lastly, a friend of mine worked at AAM and said on boosted applications, that kept the WHP under 500, a level 10 valve body upgrade seemed to be more than enough to handle to power. If this is the plan, I'd throw in an upgraded Sebring cooler for peace of mind and call it a day. Going any more than that though, you may want to consider the bullet proof build.

All new automatic transmissions are not tune to the fullest capacity, and thank God for the workers who got fired from car manufacturers that saw that they where ripping faithful customers and just human beings in general, they came with great products for the aftermarket consumers. I want that level 10 transmission since 2013 but my car was to new and still has 96,000 miles for being a 2010. I'm about to purchase that tmcmotorssport black auto flash gearing tool just because the old school one was the first one to exist and ofcourse is going to have flaws but the new auto flash works way better. This tool gives you instant torque and horsepower specially if you have a uprev or tune. Search Transmission Control Unit Module and you will exactly understand me and the TMC Motorsports TCU Flash autogearing. Happy motoring.

Uhm...

'The all-new TCU Flash Tool integrates with the vehicles onboard communications network via OBD to access the ECU, TCU and Convenience modules to adjust/reset the shift strategies within the OEM (Original Equipment Manufacturer) control components to "point" or “re address” these strategies to the best and most optimal settings.'

'This includes changing the transmission shift speed pointer to a faster/different setting. The internal components that make up the mechanics of the transmission have a wide range of tolerance and multiple settings allowing manufacturers in most cases to use single components across a whole range of vehicles, from a VW golf to a Lamborghini Aventador. They all contain similar if not the same generation components, usually built in the same factory, but have model specific programs that are used for their specific application.'

No.

The fact their "explanation" is all transmissions are the same should be more than enough reason to give this snake oil a wide birth.

sure man, that's what I tought it was snake oil but is not, search what is a tcu online and how its connected to the obd2, you know that after they sale you a car it says it has amount of h.p. and torque, next 3 years the same car, the same engine and same transmission has more horsepower then the last three years old model. You know it's a tune on the TCU and on the motor.
I'm 100% sure that you are those car salespersons even if you say you ain't.

I know you are salesperson who doesn't want the truth to be out cause you lose money.
all brand new Automatic transmissions use a TCU that communicates the ecu or vise versa to do everything you said Uhm and No too. Just research in Google what a TCU does and it will tell you. All transmission are either single clutch, dual clutch, pdk, or other types that are made with a tcu too control so tell me how is this snake oil?

What in the..?

If that's how you interpreted that all encompassing explanation you should probably pump the brakes on shelling out money for a products that the manufacturer can't even explain...

https://www.audiworld.com/forums/s4-...g-box-2816093/

Then again, you seem to jump at the opportunity to endorse products that have absolutely no results: https://www.myg37.com/forums/engine-...ml#post4107700

Your money. Burn it how you see fit.

Haha Haha, whybsuch hate with a TCU tune, you are a salesperson who wants people to believe you that they completely redesign the transmission and made it better. You swear manufactures want to make new transmission in the end for cars if all they need to do is a TCU tune, just like how the motors get tune. Why can't you see that there is a tune on the transmission control by manufacturers

I know that there is a lot of **** snake oil out there but I know for a fact that the tool works exceptionally on my Mazda 6 skyactiv if you where to drive it you will be like what the heck what's dome to transmission right away. Its crisp, fast, and smooth like butter before the TCU tune it lag, and all my cars are completely modify so I know what is snake oil and what is not. I'm sorry but this time this tool is not snake oil. Best tunes come from the U.K. and the U.S.A,band this particular one was made by Porsche and top manufacturers ex employees who saw exactly how you salespersons and manufacturers pull tricks on customers and they are making **** loads of money without being greedy.

No hate.

Actually, I'll include you in on this one time deal for a FOS-IV control module a local tuner is creating for me. All you do is plug into your fuse box and it initiates OD protocols in your car's TSI housing. From there, it systematically takes over your throttle bodies and consummates maps which create the same vacuum pressure in your intake manifold that one would experience after installing an 8 pd. pulley. Since the VQ is port injected (vs. Direct inject) the Intake manifold acts as a housing where the pressure can build and the AFR can occur before entering each cylinder. With the OEM VVEL system, power is always on tap with no delay.

If your interested, just send a one time payment of $799 $699 (he's having a sale) via PayPal through the gift option to my email.

Apologies for my part. The ignorance just really rubbed me the wrong way.

Bringing this back from the dead but I'm relatively certain that I can answer plenty 7AT / RE7R01A questions, especially those related to performance applications.

-John

I'm going to chime a bit on this based on the stuff that I know, accepting corrections as well. There have been a few members who went through the pain-staking process of having the Dealer "tune" the TCU which to my understanding is a re-program/update of the current software. Out of those folks a few who were tuned with either Uprev/Ecutek lost these licenses in the process being that it appears that the ECM software needs to be updated as well.
There was about 70% success from this mainly because of how much money in reality it would take to get this done as well as the inconvenience of tuned folks loosing $700+ on their tunes.

Now it's a fact that these cars record driving pattern. I have a NATS deleted ECM that I used on my car and pull it at least once a month to test other cars with. Upon re-installing it in the car I do notice a slight better shifting pattern only to revert back to the typical patterns in less than 30mins.

There have been countless of experiences of folks doing everything they simply can to improve these situations. From a total fluid replacement by 3x+ drain and fills, filter changes, line pressure adjustment in tune files as well as trying other fluids other than Nissan Matic with some confusing results at times. Sadly a few people doing it ALL and still suffering from the dead space under 3k rpm in 5,6,7 or in Drive and Drive S not helping either.
Now this part is important. There is a specific failure of the VHR that can affect this as well and is Gallery gaskets. It seems like the complaint is disassociation between when the driver expects the drop in gear vs when it actually happens.
In my experience with cars with a small-decent break in the gasket is that in this bit of time that the driver expects the VTCs are usually at 30+ degrees of advance to provide economy and need to react in an instant to accept the lower gear and provide a smooth transition.

Issues in the VTC area will and unresponsiveness when it needs to will just feel like dead-space. Now though I dont have a lot of significant data it is quite possible that the TCM expects reaction of the VTC and by not reacting when it needs to it can confuse it as an incorrect load and maintain the gear thinking you just want to go a bit up in the speed similar to using the CC to go up a few miles without dropping a gear.

I have installed 3 different transmissions in my 2010 G37s all different times using the Valve body that the transmission came with and in all honesty some where only one was a sport, another was a base G the current one is a base Z transmission and valve body. These were all TCMs that were used and proven and in neither case I had to program anything (different with a NEW TCM/Valvebody)

I believe the answer lies in a TCM tune/re-program/adjust however I believe that this can be part of the ECM as well. You cannot tune it on the common ECM flashes on it's own and like to believe that any changes done to the TCM can be lost in a ECM reprogram/flash/tune.

I can't speak on a lot of this because I've never had a customer who's had the dealer tune the TCU.
As of the last new valve body replacement (tcu really), the customer got one that was plug and play, and swapped the new electronics onto his existing IPT modded valve body. Everything worked correctly but it appears that there may be another mechanical transmission malfunction internally (gear ratio error).

The P0730 which is the code for the incorrect gear ratio is for the 5th speed sensor that reads the gear of the shaft, I've found that 50% of the time is a dead sensor and the other half is metal contamination stuck to the magnet of this sensor.
Because this is part of the valve body components it usually doesn't come included. Unsure if this helps

Thank you!
The original problem wasn't the typical P0720 (I'll find out the exacts because the car is 100's of miles away from me being diagnosed) and I don't have the original codes in front of me- one of them was a communication error though. The original codes are all gone after the tcu swap.

There's 3 speed sensors in the unit, two are built into the valve body (which are new at this point) and there's one in the tail that reads the parking gear for all output shaft speed.
Also, it currently has a gear ratio 6 code only, my guess is internal issues.

Maybe relevant to this thread or at least of interest to you guys:

@IPT_Trans

If one were to order your Upgraded RE7R01A Performance Automatic Transmission here: https://www.importperformancetrans.c..._detail&p=5437

Would this purchase include the following?
RE7R01A Transmission Rebuild Kit not shown on this page, but similar in make up to the others shown: https://www.importperformancetrans.c...uct_list&c=154
Upgraded valve body: https://www.importperformancetrans.c...uct_list&c=155
Upgraded torque converter: https://www.importperformancetrans.c...uct_list&c=152

Is there a core charge, or is the idea for us to pull our transmission and ship it to you? Do you have shops across different regions of the US that you could recommend for the install?

MotoIQ is one of the better Nissan engine rebuilders here on the west coast, but I'm not sure if you have working with them: https://motoiq.com/project-g37s-tran...pgrade-part-2/

We don't sell 7AT / RE7R01a or RE7R05A rebuild kits because A) They are proprietary B) What we do to install all of the extra clutches requires machine work and C) Not many rebuilders are very successful in building these units. (I.E. Do your research)
We do, however, sell high stall/upgraded torque converters and upgraded valve bodies

Transmission builds aren't orderable online, I do that by phone/email only as a fraud protection measure. They include the valve body work but the converters are sold separately.

We build one's existing components, as the interchange is pretty bad (really due to differences in the software that's written onto the TCM),

I don't have installation shops per say around the entire country but I do work with several shops, especially in the southeast (We are basically NYC btw)

I haven't worked with MotoIQ but judging by who I see that they are using for transmission builds, I'm sure that they will probably be contacting me in the future.

Torque Converter Installation
 

Hope that this is relevant and helpful..