Disco 3/4 Automatic Transmission FAQ - 6 Speed

Thanks Will and Gary, very helpful.

Mine had a fluid dump and steel pan conversion about 2 years / 25,000 km ago (at 125,000Km). It was great until earlier this year when I may have gotten carried away towing a heavy load up big mountains quite quickly (several times) and it's been getting testy ever since. Part of me suspects that I've just toasted the fluid (combination new and old LG6) - although the issue is far from clear as the fluid visually looks pretty ok.

I've got 2 tubes of Dr Tranny on order ... the question is do I put 12 or so litres of Nulon through it or do I put the national debt in LG6 through it ... Nulon (support Au, price is good, Wills posts on the issue are encouraging, cheap enough to treat to an annual change ...) vs LG6 (RIP OFF, but OEM spec ... ) ... decisions decisions decisions ! My plan is to change and flush with whichever fluid and then if it is not improved after a couple of hundred KM then add Dr Tranny ... if it is not improved then ... back to the drawing board I suppose.

I cannot help with your question as I have the same delemma - so I change to Nulon (cheap but there is a risk) or stay with LG 6.

What I can say though is only put in enough Dr Tranny to do the job, that is the right amount of Dr Tranny for 9.5 litres (the dry fill amount for the gearbox). From what I have read, more is not better and will cause issues with the TC - I think too slippery.

So put in the just the right amount and it should work well if there is no major defect in the TC.

Garry

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Originally Posted by Epic pooh

Thanks Will and Gary, very helpful.

Mine had a fluid dump and steel pan conversion about 2 years / 25,000 km ago (at 125,000Km). It was great until earlier this year when I may have gotten carried away towing a heavy load up big mountains quite quickly (several times) and it's been getting testy ever since. Part of me suspects that I've just toasted the fluid (combination new and old LG6) - although the issue is far from clear as the fluid visually looks pretty ok.

I've got 2 tubes of Dr Tranny on order ... the question is do I put 12 or so litres of Nulon through it or do I put the national debt in LG6 through it ... Nulon (support Au, price is good, Wills posts on the issue are encouraging, cheap enough to treat to an annual change ...) vs LG6 (RIP OFF, but OEM spec ... ) ... decisions decisions decisions ! My plan is to change and flush with whichever fluid and then if it is not improved after a couple of hundred KM then add Dr Tranny ... if it is not improved then ... back to the drawing board I suppose.

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It's 3 months ago, and my memory is failing as I age... but

I seem to recall in my discussions with the chemical engineer at Nulon, that the only difference in spec was so minute that it would result in about .3 l/100km increase in fuel usage, because one spec was a tiny bit different at operating temperature.

Personally I'd suggest giving a full flush with the Nulon a go. I'd say you've burnt the LG6.

Thanks again Will and Gary.

I am pricing ZF fluid vs Nulon and having a full flush done with a proper machine vs doing a dump and pump in the driveway.

Will post what I do when I get around to doing something ... :)

Just an update to this - as I have recently changed a brake light switch and noting the interaction between the switch and vehicle systems, it occurred to me that I might get some benefit from clearing trans ecu adaption ... which I did ... shift quality has improved and as far as I can tell at this early stage the shift quality seems back to normal.

I assume that I will still have the suspected TC squealing under arduous load conditions, but I haven't been able to test that out at this point as it requires either some very spirited driving or a seriously heavy trailer and a long very steep hill at good speed.

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Originally Posted by garrycol

because the gearbox is not sealed for life (that is a furfy - not sure where it came from) and changing the gearbox oil is in the service schedule.

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It might be in the service schedule but my D4's handbook states that the automatic gearbox is "filled for life".

This may be a stupid question, but... I'm planning on the metal sump conversion and also wanting to do a complete flush of the fluid. If you do the metal sump conversion, in the process does all the auto fluid drain out (which means a full 9.5L refill), or is a certain amount still trapped inside the tranny (in which case you need less than 9.5L of LG6 fluid) ??

In a basic drain the change is only about 3 -4 litres - the rest remains up in the the torque converter.

To do a full flush at the one time the hoses on the cooler up on the radiator need to be removed and fluid pumped in and out.

Garry

Thanks Garry. That makes sense now.

Quote:

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Originally Posted by Epic pooh

Just an update to this - as I have recently changed a brake light switch and noting the interaction between the switch and vehicle systems, it occurred to me that I might get some benefit from clearing trans ecu adaption ... which I did ... shift quality has improved and as far as I can tell at this early stage the shift quality seems back to normal.

I assume that I will still have the suspected TC squealing under arduous load conditions, but I haven't been able to test that out at this point as it requires either some very spirited driving or a seriously heavy trailer and a long very steep hill at good speed.

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""No problem with your car, they all do that, just drive it till she explodes mate!""

-Every LR workshop I've ever taken my car to.