To HELP you...
Yes it is a common problem with pre 04 reg MINIs to have problems with the gearbox, which was a Midlands one. From June 2004 the gearboxes were uprated to a Getrag box which were supposed to be more reliable (although I had a 54 plate Cooper S which had a new gearbox after 22k).
Unfortunately for you, as a 2002 model I'm presuming you don't have any warranty with your car, which means BMW will charge you to replace it. You may be able to get a part payment as a goodwill gesture, but if you've bought it privately and considering the fact it's now 6 years old I'd say BMW will charge you.
There are aftermarket MINI specialists you could try which will replace the gearbox, and even fit the uprated one for you much cheaper than a MINI dealer. Depending on where you are in the country, try 1320 Autos (Beds), MODNMINI (Kent) or Mini Matt (Staffs) who will all give you cheaper quotes than a main dealer.
Just to add to that...
Don't replace it with another Midlands box. EVER. Make sure you get a Getrag box. If you're willing to splash the cash, 1320s will put a Cooper S 6spd Getrag box in your Cooper. It will be much more enjoyable to drive with 6 gears
Edited by nurseholliday, 26 April 2008 - 10:34 AM.