identifying mercedes auto gearbox

Hi I've got an early 110 with a mazda 3.5 sl tdi fitted to a mercedes 4 speed auto gearbox... the Mazda has just started knocking a little. It could be diesel knock but if its not then it will probably be more economical to fit a Merc engine than to rebuild..
I would like to know what mercedes engines will fit to this gearbox.. how do I identify which gearbaox it is?
thanks mark

Hmm find the serial or part number on it at least? Or take some pics of some distinguishing bits or shape and start looking at rwd mercedes boxes on ebay to try and narrow it down?

Hi Rattlegun was hoping someone could tell me where to find identification numbers as covered in years of oil leaks n road dirt

If it takes an om606 you may want to keep it.

love the OM616 got it in my Merc camper ..guess I'd love the OM606 50% more.... but how do I find out if it matches the Merc 4 speed auto I've got?