6 Speed Manual Trans Fluid how-to for the E9X M3s. Do all work at your own risk – this, as most trans & gear oil changes are, is a pretty straightforward flush, the only added steps are that there is a cover over the transmission housing and a transmission fluid filter, which I have honestly not seen before.
- 8mm hex head
- 8mm, 10mm, (short) 22mm sockets
- Socket extension
- Drain pan
- Fluid pump (I use this)
- 3 quarts of Manual Transmission Fluid (I used Red Line 75w85)
- New Transmission Filter (17212283111 for my 2011)
First step is obviously getting the car up. I like to get the car up on all fours to do drivetrain work, here using my Quick Jack.
There is an aluminum transmission cover under the car held on by 9 bolts total. 3 in the front, 2 on each side, and 2 in the back. The 5 front most bolts are 8mm, the last 4 in the back are 10mm. Likely will need an extension to reach the ones on the sides.
Both the fill plug and the drain plug are 8mm hex heads. The fill is located on the driver’s side, above a ridge and the drain is right at the bottom, circled below. As always, loosen the fill before opening the drain.
Once you loosen the top, crack open the bottom and let it drain. My trans fluid actually didn’t look terrible after 26k – but I like to change fluids at least every 5-10k/annually.
Replace the transmission filter. It’s held on by a 22mm socket, but there’s not a lot of room so if you have a deep 22mm, it likely will not fit. It’s a straight swap from old to new, and I happened to have a crush washer that fit, as the new one did not come with one. The torque spec is about 19 lbft
Close the drain, open the fill and pump in new fluid. Do this until it starts dribbling out, and quickly close the fill plug. I used a Plews pump from Amazon which is a pretty inexpensive and fits the Red Line bottle well. Decided to go with 75w85 GL4 – lot of mixed reports on which gear oil to use but I think the viscosity matches well with OEM. I’ve run both the 75w85 and 75w90 in the Mini with no real difference.
Once that is done, close the fill, tighten everything to 26lb ft and you’re set. I never use a torque wrench for these, I just tighten everything down around hand tight. That should be about right, as long as you don’t go crazy with the torque. Always make sure with these jobs that you’ve used about the correct amount of fluid for the job, since the only gauge you are using to determine full is that it is dribbling out. I believe I used about 2.5qts. The transmission cover goes on really easily, as you just need to slide the front part to where it was before to line everything up. That’s it!