ZF "Sealed for life" units

[rayyan171]

As always, there has been a big debate about the widely used range of ZF gearboxes in many BMW's and many other cars as well, regarding whether gearbox oil should be changed. Some of those manufacturers even say to service them with set intervals. But, upon asking a BMW independent garage, they even advised me that the oil should only be changed in the gearbox when it is leaking. With our car (E70 X5 - ZF 6HP), it involves a complete gearbox sump replacement as well. I am quite surprised at that, but I have also heard that changing the oil doesn't do any good as only 50% is drained in the process.

Should these really be sealed for life?

[Riggie]

ZF now state 70k miles or 8 years for oil change.

[rayyan171]

Riggie said:

ZF now state 70k miles or 8 years for oil change.

For 6HP or 8HP units?

[a7x88]

I have a 6HP in my Audi S6. Changed the fluid at 90k so slightly over what ZF recommended but way before Audi recommend (never!)

Sump had to be removed/cleaned (magnets on it catch particulates) and the filter also changed. As suggested - around 60% of the oil actually gets changed but it made one hell of a difference.

I’d listen to ZF and get it done

[a7x88]

ZF’s own site - section 8 and 9 have specific references to 6HP (and 8hp) so you know that page is relevant to your transmission. 100k Kms or 8 years

https://www.zf.com/unitedkingdom/en_gb/corporate/a...

[eliot]

I did the 6hp in my 750 over christmas. The sump actually forms the oil filter as well which is why it’s replaced. Use genuine ZF Lifeguard oil which isn’t cheap.

[rayyan171]

Will be seeing the indy again, I'll show him the site.

[Riggie]

https://www.ebay.co.uk/itm/bmw-zf-6hp26-automatic-...f:0

[liner33]

No such thing as an autobox that's sealed for life it's just marketing BS designed to sell more cars . Should be done every 50k or 5 years in my opinion and yes it's not cheap due to the parts and special fluod required but it's a lot cheaper than a new gearbox

[Ranger 6]

Any thoughts on who to recommend to do a full fluid & filter change in Berks/Surrey?? and how much for an 8HP?

[lufbramatt]

Not sure if it's too far to go but worth talking to Martin Hind at Dartford Transmissions. Knows his stuff and is an auto gearbox specialist rather than a general garage. Did the 5hp in my e39 about a year ago at 80k miles, zero issues since and gearchanges are much smoother and throttle response crisper. He rebuilt the shifter linkage while he was there so the shift lever moves much more smoothly too. he can drop you off at Bluewater so you're not stuck at the garage while he does the work.

He has some sort of flushing machine which can actually change all the oil rather than just the stuff that drains out.

Was around £300 for an oil and filter change.

[iSore]

The box in my old E36 323i (5HP) did 200k and on the factory fill. Worked perfectly.

On the 6 speed units. pay a bit extra and get the valve block dropped down to replace the Mechatronic bridge seal (BMW call it an adaptor) and the other tubular seals. These can harden with age and heat and allow a pressure drop causing all kinds of issues.

[eliot]

Ranger 6 said:

Any thoughts on who to recommend to do a full fluid & filter change in Berks/Surrey?? and how much for an 8HP?

It's a pretty easy job - the biggest problem for a DIY'er is that you need the car up on level axle stands and secure enough to start the engine to run the box up to temp.
I used this pump to get the oil in - it fits onto the top of the lifeguard bottle of fluid, not the quickest thing as the pipe is only like 5mm id - but it did the job eventually!
https://www.amazon.co.uk/gp/product/B008YFX1S6/ref...

My only "doh" moment was that i couldn't understand why I couldn't get it to go into gear to run it up and down the gears - this was because I had the driver's door open and was leaning into the car with my foot on the brake rather than sitting in with the door closed (safety feature). The ZF instructions actually says you need a helper to top the oil up, but i managed it on my own.

[chrisgeary]

Ranger 6 said:

Any thoughts on who to recommend to do a full fluid & filter change in Berks/Surrey?? and how much for an 8HP?

3dtransmissions in Reading did superb work on my BMW 550i a while back, full recon. I'd have no hesitation in recommending them for a fluid change.

[Ranger 6]

lufbramatt said:

Not sure if it's too far to go but worth talking to Martin Hind at Dartford Transmissions. Knows his stuff and is an auto gearbox specialist rather than a general garage.

Thanks but yes, even though it's a specialist like that I'm after he's a little far.

chrisgeary said:

3dtransmissions in Reading did superb work on my BMW 550i a while back, full recon. I'd have no hesitation in recommending them for a fluid change.

Thanks - will investigate.

[xjay1337]

Always worth doing every 40-80k depending on your driving
(Longer for lots of motorway, shorter for town).

I changed zf8hp sump and filter on my m135i, well worth doing, the old oil was horrible even at 40k.

[Andy665]

I'm having the fluid changed in my 6HP next week as a precaution. Car has done 77k and no evidence of previous change.

ZF specifically advise against a full fluid cleanse stating any oil in the torque converter should be left untouched

Been quoted 350 by a BMW specialist who will check that everything else is ok with the box whilst the sump is off

[bigdom]

Ranger 6 said:

Any thoughts on who to recommend to do a full fluid & filter change in Berks/Surrey?? and how much for an 8HP?

I had TWG in Camberley complete one on my 535d as part of a service about 40k miles ago, all's been fine.

It's not a tricky procedure, just needs to be cold and level at the start, then heated and cycled at a certain temperature before sealing up.

I've had autoboxes fully rebuilt in the past, cost about 3k, so i see this as cheaper maintenance.

[rayyan171]

Our old XC90, whilst not ZF, had a conventional torque converter Aisin Warner gearbox. We did an oil change at a very late mileage, think around 160,000 miles. This still didn't take away some slight bumps when shifting through the gears. But, not sure if this was simply age related wear, as the car was really getting on by the time we sold it.

The X5 is on around 130,000 miles. Maybe it is time for a gearbox oil change, but it is smooth shifting right now. Audi is on 80K miles (has a ZF 6HP as well) but it is rather jerky when shifting through from park to drive. It drives as smooth as can be however when in drive. I have a feeling it is because of the Quattro permanent AWD system compared to the sort of on demand system of the X5.

[Ranger 6]

bigdom said:

I had TWG in Camberley complete one on my 535d as part of a service about 40k miles ago, all's been fine.

How much did that cost?