How to prevent auto box from shifting down

Transmissions, Transfer Boxes, Axles, Drive Shafts
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Didi
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How to prevent auto box from shifting down

Post by Didi »

Hi,
About 2 weeks ago I was towing a heavy trailer with my Patrol and suddenly realised the gearbox does not want to shift down when I accelarate and the speedo cruise also does not want to engage. It shifts up normally and in manual mode everything worked 100%. The auto box fault light also was not on.I stopped at the nearst garage,check the fuses but could not find the fault so I carried on.After I stopped everything was back to normal again.I slept over in Bloem and left early the next morning and on the N1 it started again doing the same thing.I stopped again check the fuses,oil level but all was well.Back on the road and everything was back to normal.Now I was baffeled and decided I will take her to Nissan
in PE when I get there.While I was driving and trying to figure out what was wrong I started to fiddle with everything,switching stuff on and off in different sequences.When I switch the lights on the box did not wana change down but when I switch the lights off it worked 100%.I PE I disconnected the trailer and switch the lights on and all was well again.So the trailer was suspect nr1.Long story short,the globe holder which houses the stop and park lights shorted out causing the stop and park light to be on together as if you were braking.Replaced the fitting and everything worked 100%.
Then today on my way to Pta I decided to test this again by lightly touching the brake pedal and accelerating.Well she did not want to shift down.Well I understand now why the box acted the way it did because it got info that I was" braking" so it did not needed to shift down and because I was "braking"the speedo cuise will also disconnect.
This electronics can sometime baffel my brains.

Regards
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Herrie
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Re: How to prevent auto box from shifting down

Post by Herrie »

Very interresting! :thumbup:
Herrie op Safari/Patrollie
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Bruin Beer
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Re: How to prevent auto box from shifting down

Post by Bruin Beer »

Didi,
Thank you for taking the time to figure this one out and also post all the detail. :thumbup:
With the autobox so over eager to kick back I would like to have a think on how to use this to prevent the shifting back when aproaching an incline without confusing everybody behind me.
Lest see who comes up with a plan.
Bruin Beer
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Chris Skinner
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Re: How to prevent auto box from shifting down

Post by Chris Skinner »

Very well done in analysing the cause of the symptoms you experienced (can't say 'problems' as the system was actually working correctly as it was meant to!) :salute:
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Tinus lotz
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Re: How to prevent auto box from shifting down

Post by Tinus lotz »

very cool post thanks :thumbup: :thumbup: :thumbup:
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