How much transmission fluid?
 

I have a 2002 ML 320 and one of my hoses going to the transmission coolor came off leaking transmission fluid everywhere. I was able to get the hose back on and the problem fixed, but the real problem is how much transmission fluid do I put back in since it does not have a dip stick.

You can buy the dipstick from your friendly Mercedes dealer, quoting part number A 140 589 15 21 00

are you sure it wasn't a power steering hose? i thought the trans coolers were screwed on to fittings.

^ ^ ^ ^ ^ ^ ^Yes, that sounds like a power steering hose failure to me too.
That problem is covered by your Mercedes-Benz warranty for ten years from date of original purchase including towing if needed. You need power steering fluild not transmission fluild. My 2 cents.