Hi guys. Great site here. Just bought a 2006 Mini Cooper S for my kid and we love this thing. 85k miles, great shape except the transmission is acting up.
When we first got it, it would shift 'clunky' sometimes and give you that kick in the back feeling once in a while. I drained/filled the transmission 4x and filled with Valvoline Maxlife, which I read was interchangeable with the Aisin transmission fluid.
I used the procedure on here to get the level right afterwards (heat up the fluid to 95'ish degrees, car level, open the drain but don't take out the tube and let it drain until it trickles out... all while running).
Now it shifts smoothly 99% of the time, but once in a while after driving for about 10 miles it seems like it slips on the 3/4 gear upshift and will free-rev like it's in neutral for a few seconds... then all is good.
Last night it happened again to my daughter and she said she got that kick in the back when it finally got back into gear.

I didn't do a filter change when I did the fluid change... I should have.
But I'm also leaning towards possibly a bad solenoid in there.

Anyone have any suggestions to look at or to narrow it down before I just replace the whole valve body and be done with it?

Thanks.
-Mag

 

I ended up fixing this by changing the filter, using Fuchs ATF instead of the Maxlife, and turning the K2 solenoid adjuster two turns CCW. I have no idea which of those things actually did it, but my guess would be the adjuster tension change.
If the shift problems come back I'll probably put in a rebuilt valve block.

Sorry for the duplicate threads... my posts weren't getting approved yet since I'm new here... didn't realize it took a few days.

 

For the original fluid - I used Toyota Type IV - that was the factory fill. Pretty cheap at a Toyota dealer. Keep the area really clean. Did you fill from the bottom, or thru the hole up top? That was in one of the old threads. It is a good transmission, but there is a lot of heat.

 

I used the hole in the top to fill up the transmission. I have a hose that fits perfect in that hole with no leaks.

 

Good job !