How long can geartronic last if well maintained?

[XC90Mk1]

Originally Posted by Bonefishblues

Maths says you change about 2/3 of the ATF - and that's not done in an afternoon. You said you got something similar to the Horton machine in an afternoon for £60, hence my query.

Not a criticism - just assumed you'd found the Holy Grail, but you're mortal like the rest of us

I buy longer miles cars, and it's a good investment for me to have the reassurance that the one-off change has been done (esp as the XC70 'box was ever-so-slightly lumpy, and is now bob-on after taking a while to settle down)

Also the maths is not 2/3 is it?

1 dump 50%
2 dumps 75%
3 dumps 87%
4 dumps 93% or thereabouts by my maths.

93% in an afternoon for £60 odd quid, or 97% for £350?

[Bonefishblues]

Originally Posted by XC90Mk1

Also the maths is not 2/3 is it?

1 dump 50%
2 dumps 75%
3 dumps 87%
4 dumps 93% or thereabouts by my maths.

93% in an afternoon for £60 odd quid, or 97% for £350?

I think your maths fails to take into account that you're dumping new as well as old. So based on Dump 2, with the (inexact, but as a rough estimate) parameters being 7.5L capacity & 2.5L dump, a third of what you dump is the new stuff you just put in and so on. I got a bit of paper and calc'd it last night, I'll look it out - unless we have a resident maths guru that will do it for us**?

Oh, and of course that assumes that in your method you're able to get fluid out of the torque converter et al - in practice the proportion of new ATF you're dumping will be rather higher.

As I say, I'm absolutely not seeking argument, but it's an interesting discussion where one must select ones preferred horse for your course.

**Actually that would be very useful, because I do think I'm right, but mostly I'd like to know the right answer!

[XC90Mk1]

Originally Posted by Bonefishblues

I think your maths fails to take into account that you're dumping new as well as old. So based on Dump 2, with the (inexact, but as a rough estimate) parameters being 7.5L capacity & 2.5L dump, a third of what you dump is the new stuff you just put in and so on. I got a bit of paper and calc'd it last night, I'll look it out - unless we have a resident maths guru that will do it for us**?

Oh, and of course that assumes that in your method you're able to get fluid out of the torque converter et al - in practice the proportion of new ATF you're dumping will be rather higher.

As I say, I'm absolutely not seeking argument, but it's an interesting discussion where one must select ones preferred horse for your course.

**Actually that would be very useful, because I do think I'm right, but mostly I'd like to know the right answer!

I do agree with you, the proper and best way is with a good machine as shown, it’s more the fact that it’s possible to go from brown worn fluid to clean cherry red in the drive for low cost.

It’s horses for courses as you say, I enjoy working on the car and the solution is fine for me. If I didn’t want to work on it or was as happy handing over to a service shop I would pay the £350.00

[Kev0607]

That's a downside of the machine to change the fluid... the cost.

It probably works wonders & is a very good piece of kit, but £300+ for a fluid change is on the expensive side. Then again, not everyone has ramps or jacks for to do it themselves & I can understand why they'd bring it to a garage. I still wouldn't use it on my car though, but that's just personal choice.

My car had no records of the gearbox fluid being changed prior to my ownership, so its not a risk I'd take personally. If the car had regular gearbox servicing though (with records to show it), then I'd probably get a garage with one of these machines to do it (like Horton) because it does seem like a more thorough job than draining & filling (Done all at once, as opposed to over time repeatedly).

So it seems the best method for a DIY perspective is drain the fluid, replace the exact amount what you drain, drive the car for a while & then repeat the process over a period of time. I was skeptical about just cycling through the gears for a few minutes & then draining again (doing the job all in one day). Draining & filling over a period of time, with the car actually being driven does make more sense to me.

[hewking]

hi wow are you sure the filter is not replacable? if yes what difference does it make to change gearbox oil if it gets dirty again from the filter? shocking

[Kev0607]

Originally Posted by hewking

hi wow are you sure the filter is not replacable? if yes what difference does it make to change gearbox oil if it gets dirty again from the filter? shocking

The filter isn't easily accessible. You'd have to literally remove the transmission & take it apart to access it. Obviously, this is something that people aren't going to do because it would cost a fortune.

This is why its important to change the fluid.

[johnnyoro]

Hi those of you considering changing your own gearbox oil may find this useful
https://m.youtube.com/watch?v=m9bwZElsodM

[Bonefishblues]

Originally Posted by hewking

hi wow are you sure the filter is not replacable? if yes what difference does it make to change gearbox oil if it gets dirty again from the filter? shocking

Yes I'm sure. But aiui it's a mesh filter as opposed to an oil filter so not susceptible to contamination of the fluid. If a machine is used such as the one we have been discussing, then any detritus caught in the mesh will be flushed (there's that word again!) back out with the old atf.

[XC90Mk1]

Originally Posted by Bonefishblues

Yes I'm sure. But aiui it's a mesh filter as opposed to an oil filter so not susceptible to contamination of the fluid. If a machine is used such as the one we have been discussing, then any detritus caught in the mesh will be flushed (there's that word again!) back out with the old atf.

Are you sure of that? I find that really interesting as I had always wondered why they did not have a filter for changing so that would all make sense.

Interesting to know!!

[Bonefishblues]

Originally Posted by XC90Mk1

Are you sure of that? I find that really interesting as I had always wondered why they did not have a filter for changing so that would all make sense.

Interesting to know!!

Here's the item itself which aiui is mesh in housing. The reference re it being flushed I have read but darned if I can remember where - I'll have a think/look after the rugby

https://www.automatic-berger.de/TF80...lter-2005-2008