What would you guys recommend?

I have heard both Amsoil and Redline are good. Any others or recommendations? I just pretty much want the best as I want this transmission to last as long as possible.

Should I go synthetic? I am pulling the transmission so the front seal will be new.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k