my husband has a problem with his cooper these past few days, whenever the car shifts to a higher speed,it's weird,kinda hiccups..i'm not sure if the fault is- the engine misfires or hesitates on acceleration..so he'd wanna check and maybe change the atf,but doesn't know where it's located..he has also used unleaded gasoline,we're still not sure if it has anything to do with the problem, any help will be very much appreciated...thanks,,,

 

Look under the drivers side of the car you should see the transmission pan. There will be a drain plug to drain the fluid...
http://www.realoem.com/bmw/showparts...06&hg=24&fg=15

Do a search on here, the Coopers had a lot of problems with the auto trans.

 

Do you mean "regular" gasoline? It's all unleaded. If he used regular rather than the recommended premium it might cause a slight reduction in power, but it's not going to hurt anything. Still, I'd try premium just to see if you notice a difference.

 

The transmission drain plug requires an allen wrench. This will prevent confusion with the engine oil drain plug which is a 13mm bolt(needs a normal wrench). Remove the allen wrench type plug to drain out the old fluid. To add fluid, you must remove the car's battery from the box, then remove the box from it's mounting. It's all easier than it sounds- all the battery related things are removed using a ratchet, extension and a 10mm socket. Even the battery cables are removed from their posts by using a 10mm socket. Once the box is removed from the engine room, the small transmission filler plug is exposed. It's just a smaller version of the allen headed drain plug. This plug likes to freeze in place, so a light smack of a hammer to the side of the head of this filler plug may make it more easily removed with a small allen wrench. You will need a funnel with a small opening to fit into this filler opening. The owners manual says the trans takes a gallon of a BMW transmission fluid. -Jeffy.

 

is there a filter and a gasket that also needs to be changed with the cvt? how much fluid do you need to refill. thank you in advance.

 

In your glove box owner's manual it says the cvt oil capacity is a gallon. You do have to remove the oil pan installed with 10mm bolts(socket size) if you are changing both oil and filter. In this case you need an oil pan gasket. There are three bolts on the transmission oil pan that are hard to get a tool on, because they are over a stuctural member, so if you don't want to hear your husband "cussing a blue streak", have the dealer change the filter. -Jeffy.

 

hi,have changed the tranny fluid and drained the gasoline just to be sure,but it still kinda chokes.not sure if the problem has to do with the valve/canister w/ a hose on each side (i think it's the purge solenoid/tank vent)located on the right hand engine.whenever we unplug the wire,the engine has more power,less choking ,but the other problem is,the obd code p0444 (evaporative emission system)lights up.

 

Year and model of your Mini?
The P0444 is an 'open circuit' on the purge valve which will occur when the connection is unplugged. The purge valve controls some vacuum lines running from the engine to the charcoal canister tank/vacuum pump under the right rear fender liner, and if there is a vacuum leak -loose or cracked hose- it will cause poor performance issues for sure.
Problems with the tranny usually should not cause mis-firing for any reason I can think of (don't own an automatic, like to row my own), so you should probably focus on engine issues rather than tranny.
Did it start suddenly? What was done to the car just prior to the misfiring?
Why did you pull the plug on the purge valve?

 

I have found similar problem with other cars resulted from the tank being "topped up" after the nozzle kicks off. What happens is the raw fuel gets into the evap canister and creates problems when the purge valves opens and sucks gas. Bad habit to "top up" and here in Oregon where we cannot pump our own gas, I have to often stop the attendant for doing so and explain why. Hope it helps.