Question about BMW lifetime ATF in 2001 Z3

[GSEldredge]

My automatic 2001 Z3 just turned 100K miles. I was reading the BMW manual, and it says the ATF is lifetime and does not need to be changed. In reviewing old invoices, I found one from my highly regarded BMW racer/mechanic that recommended changing the ATF "as a precautionary measure." He moved away and I can't find him to ask about this. My current mechanic is not a BMW specialist. What are the community's thoughts on this? My transmission has never given any indication that it's not completely happy, as I am, driving this car (with a few modifications to make it want to turn). Regards, Scott

[GSEldredge]

Posting my questiong brought up posts with the information I needed below, so I'm good. I didn't find these when searching.

[E39 Newbie]

Just for the record, as it were, BMW's "lifetime" is defined as 100K miles. It's a polite fiction in order to make it look like the car requires less maintenance, and it reduces their "pollution" footprint by not having to service the trans "for the life of the car."

ZF actually recommends a service every 60K miles, IIRC.

[whiskychaser]

ZF stopped using the term 'lifetime' about 12 years ago and their recommendations have changed over the years. In 2009, they were calling it 'maintenance free' but recommended that you change it between 80K and 120k km in the event of severe operating conditions such as:

Frequent highway driving in top speed range
Offensive, sporty driving style


Latest recommendations can be found here:

https://aftermarket.zf.com/remotemed...e-ml-11-en.pdf

[CPHES]

How many miles? But yes, lifetime is BS. 100k is a good point to refresh, if it has not been done.

[harrier]

100% change the fluid at 100k

[hypethiz]

I had a daily auto ZHP that reached ~250k miles without any fluid change.. I don't recall it ever giving me any symptoms, but I was also pretty uneducated about this type of stuff back then so I probably wouldn't have even noticed if anything was off. the only problem I remember was a thud that it would make at very low speeds in first. but I'm pretty sure that was because of a guibo that desperately needed to be replaced.

I just changed my manual e46 5 speed trans and diff fluid today at 140k miles and it definitely gave me a little boost in performance. everything feels a bit more slick and responsive. but I also didnt feel like there were any serious issues that needed to be addressed before the new fluid went in other than some notchiness shifting into 2nd... still got that

despite these experiences I'm also gunna say that lifetime claim is bs lol

[CPHES]

If the conditions are right, high mileage on original fill can be ok. Cars that get a lot of heat soak from city driving, stop and go, it’s hard on the fluid. Drive for hours on the highway, keep the load light, and the fluid life will be longer.

[harrier]

Auto transmission failure is expensive. $6k at a shop, $1k if you diy. So spending $120 on a fluid and filter change after 20 years of service life is pretty cheap insurance!