reving up and gearbox fault?

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the car is normaly used for short runs but it dose get a good long run now and. the car had ac 72amp battery on it when i bought it that was the same size as the battery on a small car and i have just changed it for a 96amp heavy duty diesel battery that fills the battery carrier and at the moment i have had no faults touch wood i had a battery and charge system tool to see if it was charging and with the battery that was on it when i got the car with all the lights and electricals on it said charge for five hours and when i checked it with this big battery with everything on it said system ok so i will wait and see i will be happy if it cures it
 
well i put a 96amp on it and it seem to be fine at the moment but i will get a bigger amp battery for winter
 
well i thourght i had cured this problem but it seem stop have returned although this time i didnt get a gearbox fault message it seems to do it if the engine dose not fire on the first turn of the key has anyone got anymore ideas i can try please
 
I would still say your problem is battery/alternator related, or just possibly the fuse box.
What voltage do you have at the battery with the engine running?
What voltage do you have at the battery after it has stood overnight before you start it?
 
well i have got 12.8 volts at the battery without engine running (but has been started once the morning) then with the engine running i have roughly 14.6 but this charge tester my mate has tells me that i have a bad diode in the alternator but not a really bad one it has a 96Ah battery on it that i have been told it is plenty big enough
 
well i have got 12.8 volts at the battery without engine running (but has been started once the morning) then with the engine running i have roughly 14.6 but this charge tester my mate has tells me that i have a bad diode in the alternator but not a really bad one it has a 96Ah battery on it that i have been told it is plenty big enough


Wonder why Land rover fit an 107 amp one as standard then. Think you will find a diode either works or fails there is no in between. A diode allows voltage flow in only one direction. If one fails it allows voltage to flow back into the alternator from the battery flattening it.
 
well i have got 12.8 volts at the battery without engine running (but has been started once the morning) then with the engine running i have roughly 14.6 but this charge tester my mate has tells me that i have a bad diode in the alternator but not a really bad one it has a 96Ah battery on it that i have been told it is plenty big enough

As Wammers said, diodes either work or they don't, generally they fail open circuit but can also fail short circuit, If the failure mode is short circuit, it will drain your battery, if they fail open circuit your battery will not drain but the alternator output will be full of electrical spikes that will annoy the hell out of the various ECU's:eek:
 
is it possible to buy and change the diode pack on the back of the alternator then or is it a case of buying a new alternator?
 
is it possible to buy and change the diode pack on the back of the alternator then or is it a case of buying a new alternator?

You can buy diode packs, regulators and brushes, but before spending money better to correctly diagnose the fault. The alternator output needs checking with an oscilloscope.:)
 
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