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swallington

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Discussion starter · #1 ·
Yesterday when on a dual carriageway it went to shift from 5th to 6th and instead went to neutral with a clunk. I was able to get 1st and reverse only and as soon as I went more than 10mph it went to find 2nd and instead got neutral. I was also unable to select D+ or M modes, the stick would move but nothing happened on the dash. I was recovered home which took approx 6 hours and when it was dropped off the lorry D+ and M modes worked but I was too nervous to take it for a drive.

I am leaning towards this being an electrical issue and not mechanical because if it was mechanical it would be faulty 100% of the time. But that could also be false optimism for a slightly less expensive repair bill.

There is one pending error code - P0729
The EML is not on.

From the manual I have learnt this could be the following -

This malfunction is detected when the A/T does not shift into 6GR position as instructed by TCM. This is not
only caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control
valve sticking, improper solenoid valve operation, etc.

Possible cause
• Input clutch solenoid valve
• Direct clutch solenoid valve
• High and low reverse clutch
solenoid valve
• Front brake solenoid valve
• Low brake solenoid valve
• 2346 brake solenoid valve
• Anti-interlock solenoid valve
• Each clutch and brake
• Output speed sensor
• Input speed sensor 1, 2
• Hydraulic control circuit

The truck is off to Nissan tomorrow but they cannot start work until next week. I am interested to hear from anyone that has suffered anything like this with their v6.

My Nav is a late 2010 v6 7 speed auto Outlaw. 80,500 miles on the clock. Last full service was 8,000 miles / 5 months ago and this included a gearbox oil change as well as everything else.
 
#2 ·
No experience with Navara but auto Terrano (early electric gearbox) lost overdrive first and then gradually got to a similar state. Obviously not as cleaver but this happened about 80 k it was a £1500 repair by gearbox specialist.
Good luck with it not meaning to upset or worry you but please be prepared. Just in case. As all things cleaver good stuff can fail. Let's hope it's something simple.
 
#3 ·
It sounds likely to be a solenoid issue. Not heard of the V6 having this problem, but some other Jatco boxes often suffered from solenoid issues.

I would be surprised if the Nissan dealer will have the slightest clue what to do and will just tell you it will be £7k for a new box.
 
#4 ·
I would be getting an electronic diagnosis from the stealership, then take it to the best independent 'box specialist you can find for the surgery.
I agree with Landmannnn, they don't like getting their hands dirty even should(?) they have a clue what they are doing!
 
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#5 ·
Let's hope it's a sticking solenoid somewhere....
Out of interest, what the torque output of your re-mapped engine, and how many miles covered since the re-map?

If anyone knows any competent, specialist auto box repairers, it would be handy to jot a few down on this thread for Swallington, ASAP....
 
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Discussion starter · #6 ·
freemansteve said:
Let's hope it's a sticking solenoid somewhere....
Out of interest, what the torque output of your re-mapped engine, and how many miles covered since the re-map?

If anyone knows any competent, specialist auto box repairers, it would be handy to jot a few down on this thread for Swallington, ASAP....
Click to expand...
I contacted Billcar this morning and they don't know but are going to find out and come back to me. It has covered 8,000 miles since the remap.

Are you thinking the extra torque has broken the box? I would have expected bits all over the floor if that had happened but it is a fair point.

In way of an update, I've had it in to a gearbox specialist and they say it does appear to be electrical. They hooked up some diagnostic equipment and it came back with a load of CAN communication errors. Their theory is corrosion on some of the wiring. My hope is Nissan can diagnose and pin point the issue and sort the electrical side out. If there is a mechanical issue too then I will get it back to the gearbox specialist. It is on its way to Nissan now.
 
#7 ·
No it won't have broken it in 8000 miles, you have something amiss, not a catastrophic failure.
Wear is related to average torque - the standard V6 is 550Nm and the box is rated at 600Nm - so unless you are pedal to the metal, or have upped the torque massively you'll be fine.

A sensible remap should fill the torque curve out over the rev range, usually at the expense of turbo lag and extra diesel being injected, rather than up the peak torque too much, for the sake of a good sales pitch...
 
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Discussion starter · #8 ·
This has been resolved.

It went to Nissan who gave the flowing explanation.
The speed sensor momentarily lost communication with the ECM and this occured as the gearbox was looking to go from 5th to 6th. As the gearbox did not know what speed i was doing it didn't know which gear to give me, so it defaulted to neutral.

As the gearbox was attempting to select 6th gear prior to this, it determined there was a fault with 6 gear and throw up an ECU fault code for 6th gear.

Nissan checked and cleaned all earth points and cleared the fault. £85 all in.
 
#12 ·
Bargain! I'm very happy for you - auto gearboxes are fiendishly complicated (aka often expensive) !

Are you allowed to name the dealer?
 
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swallington
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