I had the stock fluid with 36k, Amsoil MTF(6k) and now Redline MTL(1k).
The MTL is way better then the Amsoil or stock fluid. I will try the Torco next time.
Not to bash on Amsoil, and I don't because I run Amsoil in the engine, t-case and diffs, but the MTF seemed to break down quickly. Started out better then stock, but then I only had say 5 or 6k on the fluid and it started shifting terrible. No grinding, just notchy and could really feel the gears/synchros. Changed to MTL and it is much better. Very happy with it. Only have maybe 1k on it though. Hopefully it does not break down and start shifting poorly again, at least not for 10k or more.
And yes I pulled the PTO cover and cleaned all the crap out of the bottom. Which I would recommend doing for sure!