Carlton ? about AMSOIL

Hey I just installed Calmin TC gears which required me to drain my new AMSOIL from my Trany. I have access to FREE 75-90 Severe Gear Oil but is GL-5 and as you know the Xterra MT requires GL-4. Being that AMSOIL is Syn. does it contain the harmful additives that Dyno. juice GL-5 has.

I guess what Im asking is can I use AMSOIL GL-5 severe gear oil in place of the AMSOIL GL-4?

From what I understand.. Yes.. it is ok for that application.

Thanks Carlton. The tech guy said it would work but did not suggest it, for what ever reason. I guess I suspected correctly that the Syn. is formulated differtly than the dyno stuff.