Disco 3/4 Automatic Transmission FAQ - 6 Speed

**swampy1** · 14th July 2015, 04:40 PM

Originally Posted by garrycol

This thread prompted me to have a chat to my local auto transmission specialist. He clearly knows the vehicles and had some interesting comments and views.

He has rarely seen any with terminal failure.

He has seen plenty that have had a rock through or cracked plastic sump - causing fluid loss. So a metal bash plate might be the go offroad.

Not seen any Landies or BMWs with coolant ingress due to the cooler being in the radiator but has seen plenty of Fords. He put it down to crappy radiators in the Fords - not corrosion related failures but fatigue cracks.

Says the metal sump is a must - for protection and ease of servicing the filter.

Does not recommend a mega flush but does insist on oil testing and changing oil on the the basis of the results.

Normal change is just a basic change as long as the test is OK. He indicated that if you leave the car up on the hoist for a couple of hours with the drain and filler holes open then you will get an extra litre or so out the drain.

If he does have to do a mega flush he does not support the drain and fill a few times method but uses the oil cooler pipe method and does the lot in one go.

He believes most of the major oil companies have ATF that are suitable for the gearbox BUT he only uses and recommends ZF 6 - he supplies the local Landrover, BMW and Ford dealers with ZF 6 when they run out.

He charges $46 a litre for ZF 6 which is a bit expensive.

He recommends that the metal sump is a must, for most cars a basic change is only needed as long as the test is OK, then a basic change, test and filter change/clean about every 50,000km.

His cost for a metal pan and 5 litres of ZF6 with labour - is $850. If a mega flush is required - there is an additional $110 labour charge and $46 per litre of oil over the 5 litres.

Garry

Garry,
Any chance of the contact details for your specialist?
Cheers,

**rar110** · 14th July 2015, 06:05 PM

I should add to my post, that despite my failure and ZF's experience with the 6hp26 generally, this is a very well regarded transmission. It's fitted to Bentleys, Audis and BMWs. Here's a pic of the wear on output shaft on my transmission which resulted in the failure. It's reportedly popping up on RRV trannys, but not really known as a problem in D3/4s. The RRV & RRS tdv8 have a ZF/LR spec number unique to these vehicles. Maybe that is the reason.
image-101436585.jpg

LuvDisco · 18th July 2015, 06:43 PM

Here we go again ! The expert mechanic has put my D3 through the mill and all the tech info from ZF and it goes like a dream in and around the city ! today he drives a short distance and gets 'Gearbox failure' - think the car is now playing tricks on us !! There is a new hand held code reader available as well that I am investing in for around $300. I do a lot of country kms and this will no doubt be my saver at some stage ! Did I mention that my D3 did not have its timing belt done till 248,000kms ! My LR dealer omitted to do ! And my new dream mechanic saved me ! The gearbox mystery lives on - I am sure it will sinc over time - will keep on travelling for now

**rar110** · 18th July 2015, 09:15 PM

Originally Posted by LuvDisco

Here we go again ! The expert mechanic has put my D3 through the mill and all the tech info from ZF and it goes like a dream in and around the city ! today he drives a short distance and gets 'Gearbox failure' - think the car is now playing tricks on us !! There is a new hand held code reader available as well that I am investing in for around $300. I do a lot of country kms and this will no doubt be my saver at some stage ! Did I mention that my D3 did not have its timing belt done till 248,000kms ! My LR dealer omitted to do ! And my new dream mechanic saved me ! The gearbox mystery lives on - I am sure it will sinc over,time - will keep on travelling for now

Apparently, there is a prescribed process to bed in a newly programmed 6hp26. Otherwise it will play up. However I don't know it.

**Celtoid** · 21st July 2015, 02:47 PM

Originally Posted by rar110

I have a RRV with the same ZF 6 speed with 240,000 km. It had a tranny service at 130 & 230,000 km. it was going great until recently when it stripped the output shaft spline. It simply wore out.

I spoke to ZF who indicated most 6 speeds (which are mostly in Falcons in Australia) last about 180,000, although have seen them last up to 700,000km.

So it sounds like you've done pretty well. ZF Sydney will do a full refurb for $4400.

Is it the same, as in identical as the Falcon's box? I thought it would have to be beefed up a bit to match it's use in a D4.

**rar110** · 21st July 2015, 04:50 PM

Originally Posted by Celtoid

Is it the same, as in identical as the Falcon's box? I thought it would have to be beefed up a bit to match it's use in a D4.

Same model box 6HP26, but manufacturer spec number, otherwise known as ZF parts list number, will be different. The parts inside vary. I was a bit surprised to find that for a D3/4 and 2.7 RRS the ZF parts list number changed many times. This could make fitting a used tranny to a D3/4 a bit uncertain. Also, it seems the casing is marked as 6HP26X (identifying external transfer box). However, the parts list number for the tdv8 3.6 RRV and RRS stayed fairly constant, and is marked as being a 6HP26 even though it has an external transfer box. So generally no hardware changes inside this box according to ZF.

reidkiwigold · 24th July 2015, 11:55 AM

hi, I just had my disco transmission oil changed at lr brighton, after speaking to there service manager, they recommended that the transmission oil be changed at 100,000 kms and at 160,000 change the oil and filter, my disco had just done 104,000 kms and the oil was black? and I don't do any towing?

**~Rich~** · 24th July 2015, 02:09 PM

Well if you want your gearbox to live a long life change the fluid every 50,000 / 60,000 k. Ignore what LR recommends on this!!!

**Melbourne Park** · 25th July 2015, 05:33 PM

Originally Posted by reidkiwigold

hi, I just had my disco transmission oil changed at lr brighton, after speaking to there service manager, they recommended that the transmission oil be changed at 100,000 kms and at 160,000 change the oil and filter, my disco had just done 104,000 kms and the oil was black? and I don't do any towing?

How much did they charge? I got them to change my oil at 11k (motor oil), and their cost for the oil was high. God knows what they charged for your transmission!!!

I tow some ... perhaps 2.5k out of the 11k so far, but I am towing the off road van to the centre and back (mostly bitumen roads though) which will be 5k. The van weighs max 2.4 tonne. I'm not sure if 50k is early enough if 50k is required for normal usage?

And is it difficult to get a sample of the gearbox oil in order to assess the need to change the oil?

I also wonder about changing the diff oils ... a mechanic (who is a Mercedes only shop) recommended doing the diffs early too. He liked the Disco too.

I wonder what the schedule is for the transfer case as well. Should it be changed as often as the main gearbox?

Ean Austral · 25th July 2015, 10:44 PM

Done my first oil and filter change at 72000 and the second at 125000. The smoothness in the trans is noticeable after the last oil and filter change just a few weeks back.

If we still have the car at 175000 it will be done again.

Cheers Ean

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