Ashamed to admit that I overlooked changing the transmission fluid at 48 mo. I switched to Mobile Delvac TES-295 Allison approved in 2012. Sent a sample to Blackstone Labs to see if any damage had occurred. No problem drive it another 10K miles. In the comments section the technician wrote "engine" but I think he meant "transmission". I changed the ATF and filters anyway, but anyone could save money by getting an analysis, vs a change whether you do it yourself or have it done. I paid about $238 for 5 gal fluid and filter kit.
I had the engine oil checked too, which I changed 11 mo ago and only 4,000 mi. It's good for another 4,000 mi. Plenty of active additive left, no reason to change it, in the comments section.