I recently purchased a base Mini Cooper with an automatic trans and about 90k miles. I don't know a full history but as soon as my wife mentioned it shifting funny, decided to do a tranny oil change. Was originally also going to do the filter, but could not manage to get the torx bolt out of the pan that's trapped under the sub frame. When I initially pulled the drain bolt, I got just over a quart out of the tranny. After unscrewing the stand tube I got a little over another quart (I only let it drain 1 hour, so I assume more would have come out over night if I had waited). Here's my question, I didn't want to under fill the unit, so I put the same amount of oil back in that came out; but if I understand the other forums correctly, there probably was too much oil in the unit to begin with because so much oil came out when I remove the plug (before removing the standpipe). To properly adjust the level, should I remove the plug and drain until it trickles and put it back in? Yes, the oil was dirty, but I'm wondering now if the shifting issue wasn't more due to an overfill condition. Am I correct in my thinking?

 

No, when I did a drain and refill I got out about 2.2 quarts total after removing the standpipe. I put exactly that much back in since I did not have any leaks. From my experience I would say that your transmission had the proper amount of fluid in it.

 

If the transmission was shifting funny it was mainly because of the break down of the ATF. But at 90k if that was the very first ATF change that's a bit long. You will have to do several changes to see if the transmission starts to shift better. You wont get all the ATF out on the first change. The torque converter holds a few quarts. The proper way to check the ATF is by leaving the standpipe in but checking it at the correct temp is key. You can try putting back in what is just drained out but these type of transmissions require the correct level or it will shift very erratic. Good luck and I hope it comes out of its shifting problem.

 

I got ~2 quarts out so I put the same back in. No problems. You should drain fill a couple more times and that's the best you can do. If you still have shifting problems new fluid ain't gonna fix it.

 

Thanks everyone for the input. Made my second change this morning. This time, after the refill, brought the tranny up to 115f, removed the drain bolt (with standpipe still in) and let it drain until a trickle. Got a little less than a quart out and now the shifting is a little better. Seems like somehow (I don't know the history), the tranny got slightly overfilled. I plan on doing two more changes, and hopefully will be good from there.

 

It's good that you checked the level. Be sure you are on level ground, not on jack/stands or otherwise at an angle.

My car was factory filled with 10k miles and less than 100 degrees. When I removed the drain plug, one quart came out. Removing the stand pipe allowed another quart to drain. We were able to pump one quart back in (with the stand pipe in place) before fluid started to drizzle out. Put the drain plug back in and dripped a quart in the top hole. Shifting is fine so go figure.

 

Can anyone tell more details on checking the fluid level. This post says “leave in standpipe but checking at correct temp” what is the correct temp and what do you do to check the level?

 

One thing this post doesn't specify - the engine needs to be running at idle when you check the fluid level. As soon as you stop the engine, all the fluid runs into the pan and that is why people think they have overfilled. It needs to be spilling over the stand pipe, at idle, and most accurately at around 100 or so degrees.