Automatic Transmission
 

I own a 2005 cooper S with 6 speed Aisin automatic transmission that is having some problems. In drive mode, would shift from 1-3rd but would stay at 50kph and goes to limp mode. Same thing happens
even if i do the manual shifting. Do I need a new transmission (its only 104,000 kms). I know that its a GF6F21WA part number. My question is, if I need to replace the tranny or is there a simple way to fix this .
If needing a tranny, would a GF6F21WA from a 07-10 cooper S fit my 2005 mini since there is an abundance of it in the US and im from Canada. The 2005 tranny are fewer and costly. Thanks for reading