I have not used it before, but I found a lot of people that had. Redline has OEM fluid replacements for both front/rear diffs and T-case. I did the fluid change almost a week ago and have put 500 miles on the truck. No weird noises or vibrations, 4hi/lo work just fine.
MV-LT replaces:
Toyota MT Gear Oil LV 75W
Toyota 08885-81007
Toyota 08885-81040
Toyota/Lexus transfer case fluid "Genuine Gear Oil LF 75W“ 08885-81080
Toyota/Scion Manual Transmission Oil LV
Toyota/Scion 08885-81001
Red Line Synthetic Oil. MT-LV 70W/75W GL-4 Gear Oil
75W85 GL-5 GEAR OIL replaces:
Toyota/Lexus 08885-02506
Toyota/Lexus 08885-02606
Toyota/Lexus 08885-81060
Toyota/Lexus Gear Oil LT/LX
Red Line Synthetic Oil. 75W85 GL-5 Gear Oil