Hello, I have a 525i 2005 Series 5 for a week. I thought about changing the oil in its transmission, it currently has 138 thousand original km, always maintained in the authorized BMW services, the previous owner, and sole owner, told me that it was never He did an oil change on the recommendation of the manufacturer (BMW). Now I have been thinking about changing it as a precaution, that if the transmission is impeccable.

Will it be necessary to change it? I ask why, it has 138 thousand km and it works well, according to ZF, this transmission should have oil changed at 100 thousand miles or 160 thousand km, and also because sometimes when you change oil and it fails later, it fails because The old oil left residues and when putting the new oil it could move particles and clog the pipes, which could generate a failure in it.

What do you think? I abide by what BMW or ZF says ...

 

Yes change it. I change mine every 50k miles. It has been discussed in this forum extensively why you need to change your transmission fluid

 

Yep. Change it, don't flush it. Use fluid that meets the spec.