If it's the little leaver on the right side of the OD than the answer is yes and secondly it's easy!
I've just done it, you'll need the oring and new roll pin.
Remove the transmission tunnel, drive out the roll pin, pry the leaver off the shaft (it needed a bit more force than I thought it would, but it wasn't excessive), fish out the oring with a pick (it will be likely as hard as an old boot), new oring in and all else in reverse. Of course top up the fluid.