Stx550 7 speed automatic information

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blackline_dave

blackline_dave

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Hey guys,
New to posting on here but long time reader of some very useful info.
I've come to realise there is stuff all information about the 7 speed auto in the 550 navaras so I've decided to start at thread to open up some information to anyone that wants to know.
First of all, this gearbox is way to electronically controlled. Slow shift changes, horrible lockup slip at the wrong time and the software was defiantly configured using a dyno and not road testing.
It's a big let down of a very nice truck.
The box is a jatco jr711e or as Infiniti calls it RE7R01B
It's used in the Infiniti G37, the 370z and a few other vehicles.
The difference between the jr710e and the 11e is the torque rating. 400nm for the 10 and 600nm for the 11.
It drives like a CVT box but is conventional step AT.
There are multiple threads with G37 owners and 370z owners complaining about the box being too 'sluggish' etc and I agree. Being an owner of a few bmws and driving a DSG box on a daily basis the jatco feels light years behind.
GTM in the states rectifies this buy doing a valve body modification or VBM for short. They then upload new software using a program and port called UPrev http://uprev.com/secure/
I've spoken with MV Automatics in South Australia about a VBM, they are going to do some research and get back to me.
The v9x engine was not in mind when this box was developed. Especially when you start pushing a bit more power and torque from the engine the issues with the box seem to worsen. It has shown on high power SC 370z that the clutch packs destroy themselves and destroy the torque convertor. The higher line pressures created by the program UPrev and the VBM help the box to not slip and provide longer life.
I could ramble on with specifics and technical information but I thought I'd provide enough info for 550 owners to do there own extra research.
Feel free to post more information to this thread!
Dave
 
A bit of good info in there. I have just sent an email off to a mob called Superchips in the USA to see if they do anything for this transmission. Some of the units they make do some awesome things for other vehicles so just waiting to hear back. If I hear anything back I'll post it up.
 
All 7 speed info you could want is here

Just found this & if anyone understands it can they simplify it for me please!

I read that they relied on computer simulation rather than on road trials for development on the shift patterns.

I'm starting to think that the box was made for the 370Z and just put in the V6 nav because where it shifts gears & the rpm's the engines at it would probably suit a petrol engine but is not so suited for the diesel engine as i feel that it should utilise the torque of the motor more & use a higher gear instead of revving to 4500rpm for 10 mins before deciding to give you your next cog!!
 
I found despite the inability to hold gears that all know it seemed to hunt more outside the torque range ie rev and make no power i only drove my mates for a few hours if that box thinks it's a petrol donk that would explain it completely.
 
There is some more technical info on the development of the box here including shift patterns, LU slip and how they use LU slip to make the box feel like a CVT box but remain conventional.
http://wk.baidu.com/view/11c9a7707f...7707fd5360cba1adb6c.html#page/1/1390855381904

The box was already made when it was matted to the v9x. All they did was change the software. The calibration for the shift changes when matted to the v9x was done without the box being inside the car.
I'm worried as the guys explained with the 370zs pumping a lot more power that the clutch pack is going to be flogged out due to the software and low line pressure letting it slip too much.
The slipping creates higher rpm as it's changing which defiantly doesn't utilize the torque from this engine.
I'll get back onto MV automatics and see what they have come up with this week.
Check out
http://www.gtmotorsports.com/product.php?productid=17840&cat=262&page=1
 
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Is the same box used in the pathfinder with the v9x?
Since the pathy set up seems to be successful, if its the same box with hill descent.
What are the differences? Valve body, electronic hardware, software?

The changes needed may be easily addressed by applying Nissan parts.

It is ridiculous that they didn't bother to get right for one and not the other 4wd.

I had the z in auto and always remarked how well match it was to the vq37.

I hope for those that have them, this can be remedied.
 
jjohn said:
Is the same box used in the pathfinder with the v9x?
Since the pathy set up seems to be successful, if its the same box with hill descent.
What are the differences? Valve body, electronic hardware, software?

The changes needed may be easily addressed by applying Nissan parts.

It is ridiculous that they didn't bother to get right for one and not the other 4wd.

I had the z in auto and always remarked how well match it was to the vq37.

I hope for those that have them, this can be remedied.
Click to expand...

The pathfinder Ti550 uses the exact same set up as the navara 550.
The hill descent control system uses the ABS to control the speed which in turn lets the gearbox hold gears.
Maybe the pathfinder Ti550 drivers aren't too worried about the lag seeing as tr SUV is set up more for comfort on road driving.

I still personally think that to run higher line pressures would rectify a lot of the issues. The best and safest way to do this is the VBM. Using UPrev gives you higher line pressure deceleration and acceleration making downshifting very harsh.
Still waiting to hear from MV Automatics.
 
There are uprev representative in oz.
They do a remap of the 370z ECU. I wonder if they know how to do the box?
 
I'm going to have a look into that. Using UPrev to up line pressure, but ultimately trying to organize a controller for in cabin adjustment. Most NA 370's aren't getting any slip in the box but I notice a heap with the 550. Maybe the high torque. So I'm sure upping the pressure in anyway will be beneficial. I'll have a look into some UPrev distributors and tuners I'm OZ.
 
So I've done a fair bit of research and calling around.
It is the same box as the 370z as stated but the TCM is completely different.
It receives signal from the ECM reporting torque due to load.
It changes the VGT (variable geometry turbo) and gear selected relevant to the torque required.
Very frustrating but shows why it will change to a taller gear when traveling up hill. The dead spot in the ECM thing before 1500rpm doesn't help this as the truck won't go anywhere if it's below this rpm.
G sensors send the signals to the ECM which in turn controls what gear the TCM should be in.
I have spoken with Croydon Racing Developments in Sydney about using UPRev to up line pressures but no software has been created yet. They could do a valve body modification but a lot of money will be spent being the Guinea pig for such R&D.
My truck is in Nissan now getting the trans oil checked and G sensors recalibrated.
Hopefully this helps to ease the slipping.
MV automatics didn't want much to do with the box as they didn't get back to me about my enquiries.
I've heard wind that firmware has been updated with 2013 BUILD trucks which link directly to the G sensors. Maybe someone can confirm this?
There are 2 sensors, one behind the dash closest to the firewall and one in the engine bay itself. Not sure exactly but hopefully someone knows?
 
Just got the truck back from a very very helpful Nissan dealer. First dealer the technicians actually knew more than me haha
Had the gearbox oil level checked and it was 1.5litres overfilled. The oil in the box wasn't drained back after initial filling when brought up over 30degrees Celsius. So every time I drove it the box built up pressure.
Bit of a worry due to the fact Nissan states that the oil level is to never be checked when servicing as it's 'maintenance free'.
Had the G sensor checked and it was SET as -30degrees. So the transmission always thought I was traveling down a 30 degree decline.
Car still has the laggy changing etc but no random up and down changes, a lot smoother changes and noticeable difference in slip.
 
A few years ago when the Turbo BA/BA-2 falcons had the BTA 4 speed auto, the box was good for standard and moderate power, but became a little overwhelemed if power/torque was increased too far without some work, the box also had more what felt like slip, but was low lockup pressure causing it.

The cheap easy fix until a T/C upgrade could be done we fitted a resistor (switched from in cab) to the lock up presure control solinoid, this told the soliniod the presure was lower than it was, causing the solinoid to hold higher pressure, giving "firmer" shifts and holding gears on trailing throttle much better.

I have no idea if the 7 speed uses external solinoids, but if it does, a quick data log with a scope will give a range of voltage operation and something could be put together.

I had a BA ute with the 4 speed auto, it was running around 325kw to the rear wheels, with over 900nm of torque from 1200rpm, I did over 200,000km in this ute with ZERO drive line issues, in full street trim inc leather seats and all options, it could run 11.9 @120mph all day long.

This ute had such a unit fitted to the Auto, took about 15 mins to fit, could be switched on and off from in cab and worked like a charm. until the control unit can be cracked, this may be an easy way to fix the lockup issue.
 
does anybody know if you are able to check the angle of the g sensors with a scan tool?

its terrible that i feel i have to tackle these problems myself because i have no trust in the dealers near me, i wouldn't trust either of them with a skateboard never mind my nav, i have had terrible experiences with both of them.

Has anyone had anything to do with zupps at beaudesert, lismore nissan or mays motors at ballina?

it's a bit of a trek for me and i wouldn't normally consider it but it's better than getting it damaged again like my other 2 previous experiences with the 2 dealers that are nearby.
 
Adam-
You can see the angle the G sensor is set at on a scan gauge with dash commander. Not sure how accurate it is as I didn't test it kn my car. My brother which has the exact same truck shows his forward back G sensor is set at -45 degrees but until he goes into Nissan and get it checked then I'm not sure how correct it is.
I strongly reccomend Kloster Nissan in Newcastle for anyone in the area after having nothing but issues in countless other dealers.
Cheers for the info Chris. That's exactly what I opened this thread for. A new way of thinking. I'll see if I can jump under the truck and check live voltages across the harness in relation to Lock up.
 
Solved..

A little off topic but still related to gearbox. do any of you guys know how i would find my reverse switch on my gbox. my 550 reverse lights and camera stopped coming on the other day all the fuses are fine and the relays are all working. checked at the fuse at the relay neither is getting power which makes me think the gearbox isnt sending the "im in reverse" signal. however i do get the reverse symbol on the dash when selected.

Also some VERY interesting ideas on the gearbox's issues i feel its a strong box and has potential for being one of the best auto box's a 4wd has had once we sought out the issues it has not being governed properly before being mated with the v9x.
 
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Hey Guys

Only New here But I also have a 2012 STX with the V6 with 52k on the clock and Love it except the Auto :deadhorse2:

Just wanting to know if anybody has had any luck with fixing the Problems ??

thanks Matt
 
Have a search, someone did a dodgy wiring work around to fix it, there's a write up somewhere.
 

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