automatic gearbox oil change needed or not?

[codered]

Dear Sirs,

I have a x5 4.4i,2000,147.000km
My car mechanic insists the automatic gearbox needs an oil&filter change.
I know the x5 book says it's lifetime guaranteed and doesn't need changing,however I've heard opinions from the mechanics saying that if the oil is not changed,the automatic gearbox will fail sooner that 200.000km .They claim to have 3 X5 gearboxes failed due to old automatic transmission oil .
So , should i change the oil&filter of the automatic transmission or not? What oil should be used for this?
I'd appreciate some professional feedback if possible.

[dkl]

What is a lifetime? Drive it until the transmission craps out? Will that be 100k miles? 150k miles? 200k miles? A few hundred dollars spent on the fluid change is good insurance for a $6000 new (or rebuilt) transmission, don't you think?

The newer owner's manuals (BMW's latest recommendation) are no longer indicating "lifetime". They are now recommending 100,000 miles (or 160934 km) for the transmission oil change. More often than not, transmissions failure are more likely due to low oil level or electronic components in them. Since BMW does NOT have a dipstick to check the fluid level for the tranny, the safest thing to do is just change it and put back in the proper fluid level.

As far as the type of fluid for the transmission, safest bet is to just pick it up from your local dealer or read the DIY article located on the main home page.

[Eurosport]

i do drain and fill every 30k-35k miles
drop pan and filter probably every other change or so
no such thing as lifetime, bunch of bs from bmw

[ljnlaw]

At a minimum I would change every 50k miles (do the diff. fluids and antifreeze flush at the same time) In my opinion paying for the preventative maintenance is worth the piece of mind.

[JCL]

I assume this is a used vehicle and you don't know the history of any previous transmission fluid changes. If you have owned it since new, then you are in a better position.

Changing the transmission fluid at that interval, if it hasn't been changed before, is likely to stir up deposits and is just as likely to cause a failure, IMO. I would leave it alone, but I would ensure there is sufficient fluid in it. I don't think there is a correlation between fluid changes and failure point. Several owners have had transmission failures around that mileage.

Do a search of this forum and you can see quite a range of opinions.

Good luck.

[Sudesh]

I read also that if you replace the fluid it must be replaced with the exact same that came out of the transmission!

[vinuneuro]

Originally Posted by JCL

I assume this is a used vehicle and you don't know the history of any previous transmission fluid changes. If you have owned it since new, then you are in a better position.

Changing the transmission fluid at that interval, if it hasn't been changed before, is likely to stir up deposits and is just as likely to cause a failure, IMO. I would leave it alone, but I would ensure there is sufficient fluid in it. I don't think there is a correlation between fluid changes and failure point. Several owners have had transmission failures around that mileage.

Do a search of this forum and you can see quite a range of opinions.

Good luck.

The transmission isn't like the engine- there aren't high pressures, and the temps aren't going to be even close- so deposits are a lot less likely to form. The other point is that synthetic atf is the factory fill. Considering that even engines don't usually have deposits when run on synthetic oil, I highly doubt an at run on syn will have any.

Fluid breaks down with heat..there's no way around that. Over the many miles, it will break down. imho, I'd change it ever 30k miles and the filter at 60k intervals.

[JCL]

Originally Posted by vinuneuro

The transmission isn't like the engine- there aren't high pressures, and the temps aren't going to be even close- so deposits are a lot less likely to form. The other point is that synthetic atf is the factory fill. Considering that even engines don't usually have deposits when run on synthetic oil, I highly doubt an at run on syn will have any.

Fluid breaks down with heat..there's no way around that. Over the many miles, it will break down. imho, I'd change it ever 30k miles and the filter at 60k intervals.

The deposits that I am referring are not so much fluid-related, as they are a product of the clutch packs and band materials wearing. They settle out in the bottom of the transmission over time. The risk is that they are stirred up when the fluid is changed, and then they tend to block passages in the transmission valve body. That usually leads to a rapid failure of the complete transmission.

There are some residues from the fluid, due to the high heat in the clutch pack. They aren't as critical as the other gunk that is all sitting in the bottom of the pan, though.

If the fluid had been changed every 30 k, then there wouldn't be the same risk now, compared to if the fluid hadn't ever been changed. Changing the fluid in a sealed unit that hasn't been disturbed for a long time is a good way to cause a transmission failure, IMO.

[Eurosport]

i definitely agree, if fluid has never been changed, etc. don't just drop the pan out of the blue and change fluid and filter

but what about, even when fluid changed with drain and fill regularly, at about 100k miles will it be safe to drop the pan and filter and change, or continue to drain and fill, that's the question i've been pondering for awhile hmmm

[The Cleaner]

Fluid chage is not needed, there is no evidence to support claims that it will make the transmission last longer. In fact from the cars I have seen, 100% of the transmission whos owners changed the fluid have failed within 10k of the change (3 cars). 100% of the transmissions whos owners have not changed the fluid have not failed (approx 15 cars). Not scientic but thats what I have seen so far.