Tranny maintenance 1999 323is Coupe

[ozarkike2]

My manual makes no reference to when the Automatic Transmission should be serviced - fluid changed .
Under “Capacities”, “ Automatic Shift ……Lifetime Fluid, No Fluid Change required “. Is the only mention .
I see I the Forum , listings of acceptable Transmission Fluid …….Should my Fluid be changed ? Confused .

[E39 Newbie]

Lifetime is the length of BMW's warranty. The trans should really be serviced each 50K miles, if I recall ZF's manual correctly. Somebody can correct me. Go ahead and service it, but if it's been neglected for 20 years there may not be much life left in the trans.

[NewB2Beemer]

I do a drain fill on all auto transmissions I own at least once a year or if driven more than 15k. If I were you I would drain the pan and fill back the exact same amount at ambient temperature (or use weight instead of volume if trans is warm). Depending on the fluid condition you can decide what you want to do but a complete flush might cause issues on a neglected AT.

AT fluid absolutely needs to be changed, there is no such thing as "lifetime" fluid as mentioned by E39!

(I don't know anything about E46 ATs as ours is manual, I did change the manual fluid when we bought the car for our teenage son).

[NewB2Beemer]

As a reference this is what the fluid looks like when drained from a brand new SUV after a mere 15k miles. It is not too bad but far from clean.


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[MarcoZandrini]

“Lifetime fluids” was a marketing ploy, and not a maintenance philosophy. Take the car to a shop that specializes in bimmers and have the fluid exchanged and a new filter installed. Do not have a transmission flush performed.

[dworthy]

+1

Fluids wear, and while with a sealed transmission you can go 75k miles, it still needs to be replaced.

However with a car that you don't know if it's ever been replaced, sometimes it's best to leave well enough alone.