TD5 auto-box oil change

I would like to change the transmission fluid in my 2001 TD5ES and have had a chat with my indie who will do it as part ofthe next service. However, Difflock state that these are sealed for life units that do not need fluid replaced.

http://www.difflock.com/servicing/ZF-auto-oilchange/ZFauto-oilchange.shtml


Have many people changed their auto fluid, is it worth it, does it make a difference? My disco has 42k on it now, but if 7 yrs old.

Cheers for opinions

Have same car exactly year and model, just done all my oils and filters, had big troble with box, read all threads from ttam lleb or big matt, and see the replys, last one said do not change auto box oil and gave me link to transmission company who basiclly say the oil you use to replace is like a detergent and it then cleans your box, thus blocking the govoner valve??? mine ok now as had not replaced enough oil, hope this helps mate. the posts are only over the past week so you should find um no probs