Until the Toyota engineer that specified this stuff speaks up, anyone saying “not a concern at all” is making statements from a place of ignorance.
You MIGHT be fine. You might not. What we do know is Toyota changed the spec around the same time of some internal parts differences in the transfer case. Also the unicorn piss has significant differences in color and odor, which suggests altered chemistry as well.
That said, the ravenol product explicitly meets Toyota’s published spec, is much more affordable, and they make great products in general.
We also know the whole reason lube manufacturers still produce “MTF” type fluids is the friction reducing additives that let GL5 gear lubes do their job so well also happen to attack the yellow metals commonly used in synchros.
The thread I started discussing the topic in lots of detail:
I'm baselining my new-to-me 200 and part of that process is all new fluids. Looking up the specs, Toyota calls for "SAE 75W Toyota Genuine Transfer Gear LF" fluid. 1.53L, for the record. My discount parts source is $53.63/Liter, MSRP at the counter is $81 What about this stuff is so special...
forum.ih8mud.com
I personally run the ravenol product now.