[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

[UnluckySaxon]

I find the mention of 'lifetime free' a red flag so I asked my usual Indy on their opinion. He said 'lifetime' is about 100k miles, so there.

He quoted me best part of £800 to change the sump filter and refill with the specific oils, which made up the bulk of the costs.

[Tommo3]

Originally Posted by spicyB48

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.

Just go over the dealers head to a higher authority, BMW themselves. They will tell you to look in the handbook which says it is good for the life of the car. You bought a car with the box fitted and didn't just buy a box on its own so why would you not believe BMW?
You could ask hundreds of BMW specialists and mechanics, those that need work will tell you to change it. Looks like you have made up your mind what you want to do.

[Tommo3]

Originally Posted by F32Fleet

This is ZF's current stance on the matter.

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

Fine if you bought your gearbox from ZF, but you didn't, you bought a car from BMW who you made a contract with.

[Tommo3]

Originally Posted by UnluckySaxon

I find the mention of 'lifetime free' a red flag so I asked my usual Indy on their opinion. He said 'lifetime' is about 100k miles, so there.

He quoted me best part of £800 to change the sump filter and refill with the specific oils, which made up the bulk of the costs.

I love it when people think that their local independant knows more than the people who designed and built the car. Perhaps he needs the work so is not as independent as you think!

[F32Fleet]

Originally Posted by Tommo3

Fine if you bought your gearbox from ZF, but you didn't, you bought a car from BMW who you made a contract with.

LOL and you don't think BMW has been using ZF because their transmissions are designed with "lifetime fluids" under normal operating conditions?

BMW only cares about warranty and the max warranty you can get, in the US, is 10 yrs/120k miles.

Drivers in the US expect 350k km or more from their cars. ZF gives owners a path to getting there.

[Tommo3]

Originally Posted by F32Fleet

LOL and you don't think BMW has been using ZF because their transmissions are designed with "lifetime fluids" under normal operating conditions?

BMW only cares about warranty and the max warranty you can get, in the US, is 10 yrs/120k miles.

Drivers in the US expect 350k km or more from their cars. ZF gives owners a path to getting there.

ZF might be giving a fluid change interval because they sell boxes that are fitted in all sorts of cars. When their box is fitted to an 800 hp monster car, the oil might suffer within 100,000 miles, but when in a 200 hp BMW it will have a much easier life.

[UnluckySaxon]

Originally Posted by Tommo3

I love it when people think that their local independant knows more than the people who designed and built the car. Perhaps he needs the work so is not as independent as you think!

Tommo,

I've had bikes and cars from BMW - The only time I've had problems with either is after a BMW main dealer has touched them, and have had to take them back multiple times to put the issues right.

Whilst I have a mechanic qualification, it isn't my business practice so I prefer taking it to indy BMW specialists.

If you have a good BMW main dealer that look after your car well, good for you I'm happy.

Equally, if you think that oils are 'lifetime' then that's also fine.

[Tommo3]

Originally Posted by UnluckySaxon

Tommo,

Equally, if you think that oils are 'lifetime' then that's also fine.

You must be a politician, I never said that I "think" I said that BMW tells me.
Your BMW indy would never give you information because he needs some business would he? He is a BMW indy to make money from you.

[spicyB48]

Originally Posted by Tommo3

ZF might be giving a fluid change interval because they sell boxes that are fitted in all sorts of cars. When their box is fitted to an 800 hp monster car, the oil might suffer within 100,000 miles, but when in a 200 hp BMW it will have a much easier life.

I think you might be on to something. Still, I guess a transmission oil change is a good idea.