I have been looking around the board and getting confused on fluid types and whether I should change my tranny fluid at all. Most of the discussion seems to be about 530's and 540's with "lifetime fluid" or 525's.

I have a 1989 535iA with 69k miles and I was considering an ATF fluid change because it seemed like good preventive maintenance. I was leaning toward the Royal Purple ATF. I need some opinions on whether I should do it, and if I do it, how much fluid I will need.

Any preferred methods?

Thanks in advance.

Mark

I used amsoil a few years ago, no problems.