I ran one Jaguar with a ZF 4HP22 to 227K miles, and another Jag with a ZF 4HP24 to 178K miles on their Dex III and both trannies were like new when the cars went to new owners.
I do drain the tranny pan with every oil change, however. Pretty sure there is WM Dex III in the 4L80E in my Xj12, but its only got about 72K on it. I think Wally's synthetic ATF is in the 4L60E in the Blazer, and there might be some in the GTO.