Change transmission and differential oil, BMW E87

 BMW prescribes "lifetime fill" on the manual transmission and differential. Well, when the consider "lifetime" ten years or 150000 km, that's works well, but my car is past one and almost past the other, so I decided it was time to refresh those fluids. Even though the oil in those components doesn't wear like engine oil, it will absorbs some particles from wear and tear, and temperature changes will also cause moisture. 

Transmission:

I ordered Castrol oil of the right spec:

Castrol Syntrans B for the transmission. It needs about 1,6 liter in total. This oil is for the transmission only, not suitable for the differential!

First, you need to take off the plastic noise and splash shield:

Then, find the fill and drain plugs:

Fill plug in RED, drain plug in GREEN. Pretty obvious. Always remove the fill plug before the drain plug - in case something happens so you can't get the fill plug out, it will be quite challenging to refill the transmission through the drain plug. ;) 

I drained the oil, which was not too bad, but more a dark brown color than the light brown new oil, so I guess it was a good time to replace the oil now. Refilled the transmission until oil came out of the fill hole - then the level is right. It only takes about 1,6-1,7 liters.

Put the noise/splash shield back on, and you're all set.

Differential:

For some reason, BMW decided that having a drain plug was not a good idea, so they made this differential with only a level/fill plug. That means you have to find a way to suck the oil out using a big syringe or some other suitable equipment. I used a pump that was made for some motorbike fork oil change, that I picked up at the local car parts store for cheap. The oil in my differential looked quite okay, light color and probably just fine.

I could get around 0,8 liters out in total, and refilled it with the appropriate Castrol differential oil, weight 75W-90, that I forgot to take a picture of. No standard E87s were made with a limited-slip differential, so it just takes standard final drive oil - synthetic is recommended. Refill until it drips out of the hole and put the plug back in. Make sure the small, green O-ring is in place before putting the plug back in.

Now you can drive for many more years knowing that no old and worn oil is in the system! :)