dampowers

hello

i am new to the fourms and to mercedes
i have just bought a 1999 c230 kompressor this car has 146000 km on it
the car is a one owner car and driven by a 80 yr old lady
the car runs very well and in very good condition
i have 2 questions
when i took it for a test ride the tranny was slipping this is a sealed unit with no dip stick i read in the owners manual that when there is a problem with the tranny it goes into "limp mode" is this so no damage is done to it
the tranny it is going in to get service next week to see the cost
question 2
there is a misfire in cylinder #2... does this cylinder gets shut down when there is a problem firing cause it seems to have a "noise" coming from the top end
what is spark knock noise would this be my "noise " i hear
here is the kicker i bought this car for 200.00 cnd
if the drive train is done it is not a big cost to me
i can put a link to utube so you can hear the "noise" if this site allows it
all comments welcome

Darrin