[spicyB48]

I asked my service advisor at the dealership and they said the transmission in my 2019 330i has lifetime trans fluid and therefore is maintenance free. However, I have read elsewhere that transmission fluid needs changing every 50-60k miles, and a local independent mechanic also recommends transmission fluid changes.

Who is right? I trust my service advisor at the dealer, but on the other hand, lifetime transmission fluid seems a bit suspicious. However, I saw people have had cars go to 200k without trans fluid changes, and Blackstone oil analysis shows no issues.

[peelerec]

Originally Posted by spicyB48

I asked my service advisor at the dealership and they said the transmission in my 2019 330i has lifetime trans fluid and therefore is maintenance free. However, I have read elsewhere that transmission fluid needs changing every 50-60k miles, and a local independent mechanic also recommends transmission fluid changes.

Who is right? I trust my service advisor at the dealer, but on the other hand, lifetime transmission fluid seems a bit suspicious. However, I saw people have had cars go to 200k without trans fluid changes, and Blackstone oil analysis shows no issues.

It’s dependent on your risk tolerance and what you believe is best practice, as well as your driving style. It doesn’t hurt to be proactive and change all fluids early.
Personally, I had trans and diff fluid changed @ 40k. I also do oil changes every 5k as well as before/after track day. Is it overkill? Maybe? Would I rather be overkill and proactive, rather than reactive and cause damage…..

[cyam]

The recommendation by the manufacturer of the gearbox is to change the fluid at 50,000m / 80,000kms and at those intervals after that.

Do that if you intend to keep the car for some time.

[pmeister42]

My dealer suggested changing it between 60k-80k miles (and they want $1800-$1900 for it). I'll probably do it between 50k-60k along with the transfer case and diffs.

[cyam]

Originally Posted by pmeister42

My dealer suggested changing it between 60k-80k miles (and they want $1800-$1900 for it). I'll probably do it between 50k-60k along with the transfer case and diffs.

Rear diff (esp on M340i) I'd do at (and every) 30k miles (its super easy and relatively cheap) - can easily do yourself.

Gearbox, front diff and transfer case at (and every) 50k miles - gearbox is a lot more particular in the way fluid is changed - quite a procedure. You can do it yourself if you REALLY know what you need to do, but the risk if you don't do it right is real.

[spicyB48]

Originally Posted by cyam

Rear diff (esp on M340i) I'd do at (and every) 30k miles (its super easy and relatively cheap) - can easily do yourself.

Gearbox, front diff and transfer case at (and every) 50k miles - gearbox is a lot more particular in the way fluid is changed - quite a procedure. You can do it yourself if you REALLY know what you need to do, but the risk if you don't do it right is real.

At my next oil service I'll ask the dealer again, if they mention the whole "lifetime fluid" thing I might just go to a trusted BMW specialist. I definitely don't trust myself to do the trans fluid, but the diff is easy from what I heard.

[aviciiavbdeadpunk]

https://www.bmwofturnersville.com/se...ance-schedule/

other dealers will actually do it..... some dealers would rather you have a burnt trans and sell you a brand new one for 10k-15k

[Schantin]

Originally Posted by cyam

The recommendation by the manufacturer of the gearbox is to change the fluid at 50,000m / 80,000kms and at those intervals after that.

Do that if you intend to keep the car for some time.

^^ Exactly ^^ ZF recommends fluid changes at 50K mile intervals. If you plan to keep the car past that point, it's worth following their recommendation.

Doing the fluid / filter change wasn't that big of a process. I did the trans service on my 2022 330i last month. It took about 2 hours total while taking my time and referencing a couple YouTube vids.

[F32Fleet]

Originally Posted by spicyB48

I asked my service advisor at the dealership and they said the transmission in my 2019 330i has lifetime trans fluid and therefore is maintenance free. However, I have read elsewhere that transmission fluid needs changing every 50-60k miles, and a local independent mechanic also recommends transmission fluid changes.

Who is right? I trust my service advisor at the dealer, but on the other hand, lifetime transmission fluid seems a bit suspicious. However, I saw people have had cars go to 200k without trans fluid changes, and Blackstone oil analysis shows no issues.

This is ZF's current stance on the matter.

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