Originally Posted By: camrydriver111
Overkill. It's like changing your oil at 2000 or 3000 miles.
Following the factory interval won't damage your transmission.
I only changed mine after 160k km and 10 years on a transmission with "lifetime fluid". I'm at 230k km now and there is no issues.
Not saying that you haven't been fortunate enough to have your fluid last 100,000 miles without incident, but that doesn't mean that it's not beneficial to do it earlier. You may have just been lucky. Lack of apparent evidence of damage does not mean that it wouldn't have benefited from earlier change.
Also, just because your car's trans did okay with a 100k mile interval, doesn't mean that all cars should. Fusion manuals spec a 100,000 mile interval, but any Ford tech worth his salt will tell you that you're better of doing it much more frequently, and most will tell you to do a drain & fill every 30,000 miles. Some transmissions are just harder on fluid, and any trans that doesn't have a user-serviceable filter (like the 6F35 trans in the Fusion) will definitely benefit from an earlier drain&fill.