Thread: Disco 3/4 Automatic Transmission FAQ - 6 Speed

The LR instructions for fluid drain and refill indicate that the sealing washers for the drain and fill plugs should be discarded and replaced with new ones. My googling hasn't been good enough to find a part number. Does anyone know the relevant part number (or whether a generic sump washer would be ok) ?

It's a plastic pan and from memory the plastic drain plug has some kind of rubber o-ring on it to seal. You definitely can't use a copper washer but if you want to replace it, I'm sure you could find an o-ring that would work. I didn't bother with mine and it never leaked. Then I replaced it with a steel pan that doesn't even have a drain plug.

The fill plug is metal however, so like the transfer box, if you have a kit of copper washers you shouldn't have any troubles finding a replacement.

Epic pooh you sound a lot like myself, probably a little bit too concerned about these things. I wish I shared the 'turn the stereo up' mentality, but to a car enthusiast, one's car is a reflection of themselves and I'm pretty meticulous with details!! My trans has never been 'right' in my opinion, but I've taken it to a few people now and noone seems to think there's anything wrong with it, even though it makes literally a host of different noises at different stages. I believe most if not all of the noise is coming from the converter, so at some point I'm going to pull that out and then pull the rest of the trans to bits and see if there's anything else that could be making noise and replace it. Then if there's still problems, remove valve body and see if I can get it repaired.

There's places in the US (like Sonnax) that repair mechatronics, I'll have to see if somewhere here does it, or maybe find a low low km Falcon/Territory one and swap the computers over.

Originally Posted by Rich84

Then I replaced it with a steel pan that doesn't even have a drain plug.

Is that right? So I guess you have to suck the oil out which is a bit of a pain.

Is it just your steel pan (what brand) or do all steel pans lack a drain?

Cheers

Garry

That's right - no drain plug on mine at least. I bought it from a transmission specialist here in Adelaide - the invoice stated if was for a Falcon/Territory.

It's an aftermarket unit with a laminated paper gasket but still has the two magnets etc. I don't know whether any genuine ZF pans don't have the drain plug for various models, I have heard either the Ford or BMW X5 pan doesn't have one.

I would've preferred to have a plug, but since it's only useful for draining the fluid, which I do through the cooler lines anyway, it does the job for me.

Thanks - something to look at when I buy mine.

Cheers

Garry

Interesting reading - AFAIK mine has not had a fluid change ever.


just clocked 103,00 kms (including a transcontinental trip in November - ~9000kms of continuous towing a camper trailer) with no real issues.


yes- the LR handbook states "sealed for life".


I am a fan of the NULON products, having used gearbox additives and oils previously (read: old school manual gogs and syncro's etc), however I am also aware of the extended warranty obligations with my D4.


From that view, I am loathe to change to a non OEM product, then in the event of damage, my extended warranty is void and I would potentially be up for a new Tranny.... Then I would rather drive it with the OEM fluid spec and service intervals and have proper recourse to LR in the event something happens.


Having said that.....
I am noticing a bit of hesitation in 1st (i.e when pulling away from an intersection, or at a roundabout, as well as when shifting from reverse into 1st. Will ask at next service if they can clear the ECU error codes 9 have found in the past (on bikes etc) that this can dramatically improve response.

I'd suspect the following:
-trans fluid needs to be replaced -and/or-
-if you or someone else has been driving it hard you'll notice the trans will hold gears longer. The trans ECU adapts to driver behaviour and wear within the transmission ie clutches etc up to a limit. You can clear these adaptations which will force the trans ECU to learn new adaptations based on how you drive now. -and/or-
-You have one front tire worn slightly more than the other, hence one wheel is spinning slightly faster than the other. This causes the trans ECU to think you are turning a corner, and it will not change gear. The difference could be small enough that the symptom is still intermittent -and/or-
-Faulty brake light switch - trans will not change gears if it thinks your foot is on the brake. Often you would get cascade faults with that as well if something is shorting out.

As you're at 100K+ I would do a double flush (at least) using LG6 or an OEM substitute (Shell/Ravenol etc) that was developed for this trans. I'm not convinced by the other brands' "Multi Vehicle ATF" - I'm not saying they don't work, they just haven't worked for me. You can replace the pan with the metal one and replace the filter at the same time.

I'd follow that up with clearing the transmission adaptations. The two actions together will more than likely clear up any driveability issues you are having, except for maybe the reverse to 1st problem - what exactly is happening there?

Of course, check with LRA first to gauge their position on you carrying out service work that is not scheduled by them (but is still required nonetheless).

Originally Posted by Rich84

I'd suspect the following:
-trans fluid needs to be replaced -and/or-
-if you or someone else has been driving it hard you'll notice the trans will hold gears longer. The trans ECU adapts to driver behaviour and wear within the transmission ie clutches etc up to a limit. You can clear these adaptations which will force the trans ECU to learn new adaptations based on how you drive now. -and/or-
-You have one front tire worn slightly more than the other, hence one wheel is spinning slightly faster than the other. This causes the trans ECU to think you are turning a corner, and it will not change gear. The difference could be small enough that the symptom is still intermittent
-and/or-
-Faulty brake light switch - trans will not change gears if it thinks your foot is on the brake. Often you would get cascade faults with that as well if something is shorting out.
As you're at 100K+ I would do a double flush (at least) using LG6 or an OEM substitute (Shell/Ravenol etc) that was developed for this trans. I'm not convinced by the other brands' "Multi Vehicle ATF" - I'm not saying they don't work, they just haven't worked for me. You can replace the pan with the metal one and replace the filter at the same time.

I'd follow that up with clearing the transmission adaptations. The two actions together will more than likely clear up any driveability issues you are having, except for maybe the reverse to 1st problem - what exactly is happening there?

Of course, check with LRA first to gauge their position on you carrying out service work that is not scheduled by them (but is still required nonetheless).

Doesn't seem to be holding gears longer - Idrive it normally (70% freeway on cruise control but put the occasional"boot in" just for kicks and that awesome 3.0L TTV6
Tyres are worn - I believe they will be OKfor this summer


No issue with brake lights or switch AFAIK,both boat and camper trailer (with electric brakes) are working fine. Interlockwith brake is also working fine.
Sounds good - will follow that up shortly.


Select "R", reverse out ofdriveway (or carpark etc.), brake, select "D" and she hesitates for1-2 seconds, then 'clunks' into 1st quite roughly. even with engine/trans attemp and vehicle fully stopped.
Thanks - will do