DIY: 6MT Transmission Oil Change

Z K wrote

The dealer doesn't replace the transmission fluid for me. They say it is supposed to be a lifetime fill so they won't touch it. I ended up doing it myself. I will say the transmission shifts much smoother with fresh fluid in it.

The spray bottle idea is actually pretty cool! I hate the pump things that the auto parts places sell.

If you are running quick lap times and have a considerable amount of miles on the car then a change around 50k is a must.

JamesKilcarr wrote

hi, im going to change mine myself, i was just wondering what the correct oil level should be at all times? after i double check it a couple times after running the car in gear and test driving it, should it always be pretty much full? i just wanna make sure i don't put too much or too little, thanks!

When the transmission is full and the car is level, it should be dripping ever so slightly out of the fill hole. After filling with oil the first time and taking it for a drive, I rechecked the fluid level and it wasn't over flowing. A little bit more fluid was able to go in before it overflowed. I thought this was most likely due to the transmission cooler taking in some fluid since it may have emptied when I drained the old oil (I let it drain for a long while although it's not necessary).

okay so it should be full when im finished with everything and its been tested and checked, also did you notice a big difference in the way the transmission feels with new fluid?

JC919 wrote

If you are running quick lap times and have a considerable amount of miles on the car then a change around 50k is a must.

I changed mine. I was just saying that the dealer doesn't change it for me.

I do not believe there is any "lifetime" fluid on automobiles. All things wear out over time. It's just BMW's excuse to get out of paying for maintenance.

JamesKilcarr wrote

okay so it should be full when im finished with everything and its been tested and checked, also did you notice a big difference in the way the transmission feels with new fluid?

I felt a noticeably difference immediately. Smoother

Z K wrote

I changed mine. I was just saying that the dealer doesn't change it for me.

I do not believe there is any "lifetime" fluid on automobiles. All things wear out over time. It's just BMW's excuse to get out of paying for maintenance.

+1 On a performance car like this, I don't believe in lifetime fluids. It pays/saves to be cheap and BMW is getting good at it.

jjw2331 wrote

+1 On a performance car like this, I don't believe in lifetime fluids. It pays/saves to be cheap and BMW is getting good at it.

Thanks for the writeup! Will do this the next time I change my oil. Will also do coolant flush (or as much as I can from the 1 drain bolt) and put some fresh ATE Blue in the M3.

Just did my tranny and diff oil change. Want to say thank you to the OP for the spray bottle idea! So much easier and cleaner than those screw on pump thingy. And cheaper too!

I think it's different on DCT vs 6MT cars. I heard that DCT transmission oil is lifetime which is why dealerships may refuse to offer that, but for 6MT cars, the tans oil is changed at 30k. Can anyone confirm?

e92zero wrote

Just did my tranny and diff oil change. Want to say thank you to the OP for the spray bottle idea! So much easier and cleaner than those screw on pump thingy. And cheaper too!

I'm glad you like it! I just learned another way recently which involves a tube and funnel that gets fed through the engine bay. You just pour fluid into the funnel. Next time I change my fluid, I'll be sure to update.

Dellort_M3 wrote

I think it's different on DCT vs 6MT cars. I heard that DCT transmission oil is lifetime which is why dealerships may refuse to offer that, but for 6MT cars, the tans oil is changed at 30k. Can anyone confirm?

You're right. DCT is lifetime according to BMW. But a member on here changed his DCT fluid since he tracks his car a lot. ECS tuning sells the fluid in 20 liter jugs. He even did a blackstone oil analysis but the lack of multiple samples makes it hard to decide what is normal and what is bad.

The 6-speed transmission is not lifetime and needs to be changed. I recommend every 30K based off Mike Miller's "Old school maintenance schedule".

Is it overkill to do this swap, let it circulate for about and week and do it again to try to flush as much of the old fluid as possible? Or is the amount left in the system without actuating the pump really not of any concern? Sorry if this is a dumb question, but this is a new area of DIY maintenance for me.

Maximusdafarmer wrote

Is it overkill to do this swap, let it circulate for about and week and do it again to try to flush as much of the old fluid as possible? Or is the amount left in the system without actuating the pump really not of any concern? Sorry if this is a dumb question, but this is a new area of DIY maintenance for me.

The amount left over is too small to need to change the system again. You can say the same about motor oil.. there is always some old oil left over after changing but no one changes it twice.

Makes sense... thanks for the response and thanks to the OP for the DIY!

jjw2331 wrote

I'm glad you like it! I just learned another way recently which involves a tube and funnel that gets fed through the engine bay. You just pour fluid into the funnel. Next time I change my fluid, I'll be sure to update.

I read about that way also but I never tried it and didn't feel comfortable doing it that way. I think when it start dripping, you have the rest of the oil in the funnel and the long tube to run down and drip out, kinda wasted. And the process of pulling the long tube out from the engine bay afterward might leave tranny oil on various parts in the engine bay from the tip of the tube. Please let us know how it works if you do try it. I will stick to your spray bottle method.

e92zero wrote

I read about that way also but I never tried it and didn't feel comfortable doing it that way. I think when it start dripping, you have the rest of the oil in the funnel and the long tube to run down and drip out, kinda wasted. And the process of pulling the long tube out from the engine bay afterward might leave tranny oil on various parts in the engine bay from the tip of the tube. Please let us know how it works if you do try it. I will stick to your spray bottle method.

Good point. Could also cap off the ends with plugs though, and then drain the tube back into the 5L bottle. I do like the spray bottle method though, ingenious!

Anyone knows the shelf life of this MTF-2?

I just read the TIS and it does not call for running any pumps. It says to drain and fill until it overflows. Not any different than any other manual tranny.

Figured I'd post since I just did this service on my car.

I used an Autologic to completely drain (and then fill) the transmission.

I'd say roughly an extra cup of fluid came out once I activated the pump.

It took pretty much exactly 2.5 liters to fill.

My strainer was absolutely spotless but the fluid was disturbingly dark (25k miles).







Hope this helps.

kaiv wrote

Figured I'd post since I just did this service on my car.

I used an Autologic to completely drain (and then fill) the transmission.

I'd say roughly an extra cup of fluid came out once I activated the pump.

It took pretty much exactly 2.5 liters to fill.

My strainer was absolutely spotless but the fluid was disturbingly dark (25k miles).







Hope this helps.

My fluid was nowhere near that dark...I wonder what it could be? Did your transmission feel okay before the change?

jjw2331 wrote

My fluid was nowhere near that dark...I wonder what it could be? Did your transmission feel okay before the change?

I'm gonna guess track time does that. The fluid sees high temps there and breaks down faster. Which is why I change all this stuff much sooner than BMW's recommended intervals.

Transmission always felt great although it does feel a little smoother since

Gotcha. That must mean I don't drive my car hard enough. I need to schedule some track days...

Thanks for posting details on the transmission cooler/pump drain! Nice to have that cleared up.

No problem!

I think I'm going to reduce my transmission service intervals to 10k miles. I don't really want to wait for the stuff to get this dark before I change it...:X Good thing is if you buy a 5 liter jug you have enough for two services.