I have about 5k miles since last drain and fill. Fluid still a bit dark but its feel and smell is very close to new fluid. Transmission just gets smoother. I may change the filter again in another 5k miles. It takes just about 3.7 L . I changed the filler and drain plugs the first time but not since and not had any leaks.

Getting better then mate
I agree with you fluid volume replacement around 3.5 Litres is what Im draining also.
If you drop the pan again and do the filter it will be interesting to see how much swarf is on your magnets, Im guessing you will have done just over 10,000 miles since the last filter replacement.

I left a litre of fluid from my first fluid change (inadvertently) in a corner forgot about it, fluid was pretty bad, its amazing how much settlement you get with the particles in the fluid. You get a clear line of sediment.
Makes me think leaving your FF for a month or two without a start up is a very bad thing, you will get a very concentrated gob of fluid from the bottom of the pan where the pick up is.
Obviously the longer you leave it the worse it is.

I'd say the cleaner you keep it the better. There is an excellent YouTube video explaining the flush vs drain and pros and cons of the flush on a very dirty transmission.

Hows doclees going?

Just dropped another 3.5 - 4 litres from the trans.
Fluid wasnt too bad this change.
Trans operation is still spot on all shifts are great.

Yes time for me to drain/fill a last time with Febi before I do the filter and go to Pentosin. Still runs better all the time. I'll be happier when a get a lower temp thermostat too.

For sure on the stat.
I did mine a few months ago, I have only seen positives from this modification.

What a very interesting and informative thread this is, thanks to all the contributors for taking the trouble to share their experiences and knowledge.

Reference the limited amount of fluid that can be drained due to the torque converter still holding onto several litres: would it be possible to drain more from the TC if the car was raised more at the front than the back?
(My gearbox is the 6HP26 on an '06 4.2 SC.) 2006MY 4.2 SC
BMW R1250 GSA Rallye TE
Triumph Tiger 1050 (sold)
1979 Pontiac Trans Am (sold)

Hadnt thought of inclining the FF, keeping in mind the drain plug location (its at the front of pan), perhaps if the pan was off it might help.

Mulcher wrote:

Reference the limited amount of fluid that can be drained due to the torque converter still holding onto several litres: would it be possible to drain more from the TC if the car was raised more at the front than the back?

The shape of the torque converter is such that inclining it by a few degrees isn’t going to make a lot of difference to how much fluid you can get out

Click image to enlarge

Even when you have the torque converter on a bench and can turn it through any angle you like, it’s still impossible to get all of the fluid out of it.

I have a brand new one in stock (i.e. completely dry) so I’ll have a go at measuring exactly how much fluid it takes to get it up to this minimum level.

Click image to enlarge

Phil

Admin note: this post has had its images recovered from a money grabbing photo hosting site and reinstated

Oh well, never mind, just a thought. Strangely, I can hear the voice of Homer Simpson saying: "Doh! Great plan, Bart!"  2006MY 4.2 SC
BMW R1250 GSA Rallye TE
Triumph Tiger 1050 (sold)
1979 Pontiac Trans Am (sold)

Update: Last drain and fill with Febi brand. Will be using Pentosin unless the cost has gone up. No pictures. Still dark but a shade lighter than last time and smells very much like fresh fluid. Transmission has continued to shift even smoother when searching for gears in downshifting for hills. There was about 10k miles from the last change. Next change will include a new filter.
I change the fluid in the morning when the engine and transmission is cold. The last times the weather was warmer and the tranny temp would go from 38c to 41c and hold util it was filled. This time it never budged over 38c. I don't know if ambient temp or reduced transmission friction is the cause. We will see this summer.

Another update: 165k miles now. I was going to do a filter drain and fill but my gasket was torn so just another drain and fill. This time with Pentosin. I had been getting the slightest sort of rare inconsistent noise primary in 5th with low rpms going up hills before a downshift. Sounded like the air pump coming on for a second or two. See what you hear when your radio is dead and you are a bit paranoid.
Fill temp was 45c. Hadn't been run yet that day.
Haven't given it the full test but on the short around the block run it seems smoother. Probably get to the filter and fluid in another 5-10k miles. Anyone have a source for a rubber gasket?

Seems to be a big difference in what comes out of the 6 speed ZF transmission when drained vs earlier GM 5 speed.
On our 6 soeed I drained out 6.5 litres of what I think is maybe a 9litre total. Paul,
2001 Discovery 2 TD5, 211,000 miles & climbing
2006 FFRR TDV8 Vogue 145,000 miles & climbing
Member of Midland (Land) Rover Owners Club, www.mroc.co.uk

Would tc change be cheaper and more comfortable at first?? 2010 3.6tdv8 180k km.
sold 06 td6 160k
Sold 03 td6 260k

Are you asking if pulling the transmission and replacing the. Torque converter would be easier? Not for me. With the Pentosin things seem even better. I can't say like new shifting because I never had one new. But shifting would sometimes upshift too soon going up a hill and then need to down shift again. Not anymore. Fluid costs me about $10 US or less per litre.