Report on Trans Fluid & Filter Change 93k 3.0

[Aimster]

Both dealerships were like the transmission is sealed and it has a lifetime fluid. They clearly said that you cannot find that fluid anywhere. They would basically be doing the flush with a different fluid.

I have a 2001.
Maybe the 2002 is different?

[dkl]

Originally Posted by Aimster

"They clearly said that you cannot find that fluid anywhere. They would basically be doing the flush with a different fluid.

I have a 2001.
Maybe the 2002 is different?

If the dealer can't find the fluid anywhere, what are they going to use when putting in that re-manufactured tranny? Is the re-manufactured transmission no longer sealed, thus using a different fluid?

[JCL]

Originally Posted by Aimster

Both dealerships were like the transmission is sealed and it has a lifetime fluid. They clearly said that you cannot find that fluid anywhere. They would basically be doing the flush with a different fluid.

I have a 2001.
Maybe the 2002 is different?

There are different fluid requirements for different models of transmissions used on the X5 (different years, and 3.0 vs 4.4) However, BMW carry the correct fluids, perhaps they don't have it in stock or perhaps they are clueless.

[dkl]

Please excuse my ignorant here, but can someone explain to me what exactly get disturb by draining out the old tranny fluid and replacing it with new fluid? If there's any particles at all that are lodged in the tranny somewhere, the chances of it getting dislodged would be just as likely whether the fluid is new or old?

The whole "lifetime (100k)" fluid sound like a planned obsolescence to me. BMW can either sell you a $6K tranny or a new car!

[JCL]

Originally Posted by dkl

Please excuse my ignorant here, but can someone explain to me what exactly get disturb by draining out the old tranny fluid and replacing it with new fluid? If there's any particles at all that are lodged in the tranny somewhere, the chances of it getting dislodged would be just as likely whether the fluid is new or old?

What gets disturbed are the particles made up of friction material from the bands and clutch packs, which have precipitated out. Draining the fluid is not straightforward, as only a portion of the fluid sits in the pan. The rest is in the torque converter, valve body, filter, lines, cooler, etc. To get the fluid out properly you have to open the pan, remove the filter, and flush out the old fluid. Otherwise, you are just replacing a portion (approx 40%) of the fluid, and mixing new with old. There are actuators, etc, that drain when you drain the fluid. Then when you put the fluid back in and start it up will select each gear and wait until it engages before driving away. You are disturbing things by that action. The valve body has very small passages, prone to getting blocked. That can cause the transmission to not shift properly, leading to overheating, burning clutches, and failure. Admittedly, that is a worst case, it is not assured. You may not cause any damage at all. Weighed against this risk, is the undoubtable fact that cleaner fluid is better than dirty fluid. No argument there. The fluid doesn't wear out, but the friction modifiers can be depleted over time. The filter is designed to keep the fluid clean. There is a chance that the fluid can get burnt by overheating, but if that is the case you need to think about what caused the burnt fluid, as it could be just a symptom.

The point is that it is a tradeoff. You need to decide whether it is a good idea to replace the fluid or not. BMW decided it was less risk not to change it. That is why they designed it as a sealed system (which is why the oxidized transmission fluid comments above seem a bit odd) Some don't agree with that decision, and that is their prerogative. Many of us believe that there is not a correlation between changing transmission fluid and extending transmission life. Just ask whether anyone ever changed the fluid and then had a failure. It is not uncommon, you can read about it on this site. If you think that BMW is conning you, and just wants to sell rebuilt transmissions, then you should go ahead and change transmission fluid frequently, and not worry about it.

[NOVAX5]

JCL, thats what i wanted to say, but you did it better.