I don't think the ZF TC deposits all the metal debris like the GM or at least it gives you loads of warning before it goes south but when my TC was rumbling we changed it out before it went totally to pieces but did a full strip measure and clean of the transmission and replaced the usual suspect seals and bearings and any plates that looked bad or measured low and also had the valve body checked over by RRPhil and it has been perfect now for around 12k miles, hopefully one less thing to worry about anyway. Under the right guidance it is really simple to work on with all the major components coming out in big lumps that can then be stripped down further.