Thanks for the reply. From everyone I have talked to or read posts from on various sites like bobistheoilguy.com say the GL-5 is too slick for the synchronizers to properly work in the Toy transmissions. I don't know how much truth there is to this, so I will probably use one one time, and the other another time, and see if I notice a difference. Right now there is dead dino sauce in the transmission and transfercase, and it provides terrible shifting when really cold (like 0 and below), and "choppy" really cruddy shifting when really hot (like 90+ out). I have heard good things about the Redline MT90 so I checked it out on the Redline website, which was the first thing that led me to the GL-5 being too slick for the synchros, so I investigated, and many people agree. I was told to steer clear of the MT90 though, because it is made out of the wrong products (I don't remember what it is, I think it is called chlorinated paraffin). So, I decided on Amsoil, because from what I have learned, if you go with Amsoil, you can't go wrong, unless of course, you put the wrong fluid in. So that is why I was going to run the GL-4 in the transmission and transfercase, not the GL-5.