ovalandrover said:

So what Data and wammers are saying is that my speedo and sat nav are incorrect sand the nanacom readings is correct?
when reading the nanacom in gearbox diagnostic it agrees with my speedo but when reading road speed in the EDC is starts to read high. please explain the inconsistancy

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Ah, new information. Either a firmware bug in the Nanocom or it's possible that the Nanocom can take the gearbox output sensor and use it to provide a speed reading, in which case the EDC reading may be being influenced by electrical noise. I haven't looked at all the speedo/ABS signal routing.

Datatek said:

Gear shifts and the power box have no connection the the speedo reading, it's an analogue instrument and they are prone to inaccuracies.

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Speed must be a factor with gear changes as if you were rolling down a hill at 50 with foot off and throttle pedel at rest it would not allow you to put it in first or should say change into first so it must know how fast its going .

Grit Valve said:

Speed must be a factor with gear changes as if you were rolling down a hill at 50 with foot off and throttle pedel at rest it would not allow you to put it in first or should say change into first so it must know how fast its going .

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Speed is indeed used in computing gear changes, engine revs and gearbox output revolutions, but not as far as I'm aware the same signals that are used for road speed. I have seen no link between the ABS sensors used for the speedo and the auto box.

Datatek said:

Speed is indeed used in computing gear changes, engine revs and gearbox output revolutions, but not as far as I'm aware the same signals that are used for road speed. I have seen no link between the ABS sensors used for the speedo and the auto box.

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That's what we were trying to find out weather the gearbox sensor was at fault with and try and check with the nano?
But it seems speed is only from the abs as far as the nano is Concerned.

Grit Valve said:

That's what we were trying to find out weather the gearbox sensor was at fault with and try and check with the nano?
But it seems speed is only from the abs as far as the nano is Concerned.

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There is an output shaft speed sensor in the transfer box. There is a output shaft speed sensor in the gearbox. These are for gear change info and nothing at all to do with road speed calculations. I explained earlier that tyres, tyre pressures, tyre wear and weight can effect speedo readings. The ABS sensors produce 8000 beats per mile this info is converted by the ECU into usable info to drive the speedo.

wammers said:

There is an output shaft speed sensor in the transfer box. There is a output shaft speed sensor in the gearbox. These are for gear change info and nothing at all to do with road speed calculations. I explained earlier that tyres, tyre pressures, tyre wear and weight can effect speedo readings. The ABS sensors produce 8000 beats per mile this info is converted by the ECU into usable info to drive the speedo.

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does the speedo take the reading from 1 sensor or the 4 sensors/ and the figure of 8000 beats per mile for 1 or all 4 sensors?
I know that the abs traction control ECU compares the difference in speed of the wheels to work.
As for the output speed sensor in the gearbox I read in rave its for diagnostic purposes and has no input to working of the gearbox.anyway this is a new sensor. I will have a look for the output shaft sensor in the transfer case.
Also am getting a reading for the gearbox that engine revs are incorrect so where does the gearbox ECU get the engine rev data from?
Is it the rev counter or the crank position sensor?
I am trying to sort out my gear change problem and have new engine temp sensor and ambient air temp sensor coming but dont think they will cure it.
(the reason for this is i posted problem on range rovers .net and got an answer back saying that engine heat sensor cured his high gear changes and the ambient air temp sensor is F***** anyway)

The speedo is fed by an average of all ABS sensors. Engine revolutions come from CPS sensor via EDC ECU. As does the drive signal for the tacho. Perhaps if you were to have described your gear change problem some advice could have been given. With the info given by Grit it seems because of the incorrect reading of number four injector that your Nanocom needs updating to BBS V1-12. Do this first there were a few anomolies with BBS V1-11.

I described my gear change problem over a month ago and the only info i got back was that it looked like it was stuck in sport mode or that i got water in the electrics neither of which were right I did get one reply from my post on range rovers .net

ovalandrover said:

I described my gear change problem over a month ago and the only info i got back was that it looked like it was stuck in sport mode or that i got water in the electrics neither of which were right I did get one reply from my post on range rovers .net

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Maybe it would be an idea to describe it again for those who may have missed it. I take it that it is revving high before changing. Have you tried disconnecting the powerbox?

wammers said:

Maybe it would be an idea to describe it again for those who may have missed it. I take it that it is revving high before changing. Have you tried disconnecting the powerbox?

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here is a copy of original post

ever since I have had this car (3 years and 60 000 miles )I have had an intermittent fault and that is when the car is going downhill with no throttle it kicks out of gear and stalls beeps and shows gearbox fault on dash. just recently it has got more frequent and also after about 2 hrs running while cruising and braking it beeps and then I lose the lock up in 4 gear. stop and restart it ok for a while.
Yesterday when going down hillon a rough road in Mongolia it stalled as it had done before but when I restarted this time the gear change pattern had changed and it would not change from first to second below 3500 rpm and from second to third below 3750 rpm .
I thought I had lost 4 th gear as I was on a jeep track and could not go over 40 mph and mostly below 25 mph.
up changes
1st to 2nd 35mph
2nd to 3rd 48mph
3rd to 4th 70mph
When I got onto a highway i had to get up to 70 mph which is about 3700 rpm before it would go into 4th and T/C lock up.
The down change are high as well .
4th to 3rd 60mph
3rd to 2nd 48mph
2nd to 1st 30mph
I checked oil level best i could on the track and it seemed OK if a bit overfull which it was not when it was checked 10000 miles ago.
Tomorrow I will drop the sump and clean out the valve block and check for debris in the sump and then decide what to do.
I have a Nanacom and it does not register any faults on the gearbox either stationary or going But what it does do is most of the time when i try to read setting or inputs is lock up or go back to Nanacom start up screen and not give any readings at all. so if I cant find any sticky valves or other faults I will try to find the LR dealer and get it on test book.
I have read Rave and there is a speed sensor in the valve block but it seems it is for sending information to diagnostic and does not do anything else.
Any one who has any knowledge of these boxes and has come across similar faults I would much appreciate any input as to what is wrong.
Thank You

Since then I have had a recon box from ashfords fitted

So you now have a new box and the problem is gone? Stalling is down to fuel quantity servo/idle control nothing to do with gearbox. Box however may have been damaged by coasting with engine stalled if done for any distance.

Additional to this you said you had a speed difference engine RPM and output shaft RPM. That is normal. The only time they will agree is with car in 3rd gear in converter lock. That is the only time there is a 1 to 1 gear ratio. In top gear with torque lock on, output shaft will be faster than engine. In all other gears apart from the scenario as above output shaft speed will be slower than engine RPM.

I have a new box but still the same fault

wammers said:

So you now have a new box and the problem is gone? Stalling is down to fuel quantity servo/idle control nothing to do with gearbox. Box however may have been damaged by coasting with engine stalled if done for any distance.

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you dont coast downhill with no power steering well I dont

wammers said:

Additional to this you said you had a speed difference engine RPM and output shaft RPM. That is normal. The only time they will agree is with car in 3rd gear in converter lock. That is the only time there is a 1 to 1 gear ratio. In top gear with torque lock on, output shaft will be faster than engine. In all other gears apart from the scenario as above output shaft speed will be slower than engine RPM.

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except for 4th gear which is overdrive then it will be faster

Dave I still recon its worth disconnecting the ps box taking out the t piece in the map pipe putting it back to the map sensor and disconnecting the box if it gone tits up its going to throw stuff out

ovalandrover said:

except for 4th gear which is overdrive then it will be faster

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I did say that.