D40 Loosing Power

Submitted: Saturday, Nov 07, 2015 at 18:22
ThreadID: 130830 Views:1495 Replies:5 FollowUps:2
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I have a Nissan D40 diesel ute with auto not shifting properly. When I am accelerating (either from a standing start or as I breast a hill) the speed rises to a point where a gear box up-shift should take place. if I am using full throttle, instead of the box up-shifting the engine looses power and my travelling speed reduces if I do not lift the throttle pedal. This initially happened when pulling in 3rd gear with a 2,000 kg caravan in tow. It is now happening when the box should be shifting up from 1st and 2nd gear as well.

If I am doing the same full throttle acceleration with a particular gear manually selected the motor will run above the gear box change revs and I can rev the motor to red line on the tachometer.

Everything happens normally when using a light throttle.

Does anyone have any theories on what's happening
PeterD
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Reply By: K&FT - Saturday, Nov 07, 2015 at 18:33

Saturday, Nov 07, 2015 at 18:33
G'day Peter

Is yours the V9X engine and 7 speed box?

I think there was some discussion on the Navara Forum some time ago but I have not kept up to date with it.

How many Km has the ute done?
Has the auto box had an oil change?

Frank
AnswerID: 592444

Follow Up By: Nomadic Navara - Saturday, Nov 07, 2015 at 19:21

Saturday, Nov 07, 2015 at 19:21
No, it's a 2007 2.5 l with the 4 speed box. The truck had travelled 225,000 km but the motor has only done about 105,000. The transmission was serviced recently and fluid was changed to see if it cleared the problem. I am going to suggest to my mechaneic that I take him for a drive with his test book attached. I am wanting to get some pointers before the trial.
PeterD
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FollowupID: 860627

Reply By: Ross M - Saturday, Nov 07, 2015 at 23:08

Saturday, Nov 07, 2015 at 23:08
I would remove and clean any magnetic pulse type sensors which are clamped/bolted into the autobox. If they, especially the speed sensor, is fluffy with magnetic crap/filings/fuzz then the speed sensor won't be able to indicate to the ECU what is happening, then it will derate the performance.

Try the easy things first.
Just changing the fluid in an auto won't alter dirty/fluffy sensor action.
AnswerID: 592450

Follow Up By: Les - PK Ranger - Sunday, Nov 08, 2015 at 00:36

Sunday, Nov 08, 2015 at 00:36
Quite probable, the wifes little Getz wasn't changing up to third as it should have, just hanging on, a new sensor on the trans fixed it.
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FollowupID: 860633

Reply By: Rangiephil - Sunday, Nov 08, 2015 at 10:56

Sunday, Nov 08, 2015 at 10:56
If the engine is losing power then it is probably engine related rather than auto related.
I had the same problem with my Discovery 2 when I bought it and it was the Mass Airflow Sensor MAF over reading and the ECU considering it an invalid reading and going to zero.
A new MAF cured it and it has not recurred in 3 years.
Regards Philip A
AnswerID: 592464

Reply By: GR8TLC - Monday, Nov 09, 2015 at 18:04

Monday, Nov 09, 2015 at 18:04
My 2011 D40 started loosing power as you described, then eventually went into limp mode, when I was crossing the Nullarbor in July. Took it to a mechanic in Port Augusta who hooked it up to an analyser and found it had multiple lean fuel errors. Turned out to be a blocked fuel filter from some dirty fuel. The fuel filter was changed before the trip, so it must of come from one of the servo's on the way over.
AnswerID: 592516

Reply By: Member - Wildmax - Monday, Nov 09, 2015 at 23:20

Monday, Nov 09, 2015 at 23:20
The cause could be that you bought a Nissan !! (sorry, couldn't resist)
AnswerID: 592536

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