Need help with gear oil selection

First off stick with GL4....Period. It is designed for our soft metal,brass,transmissions. It has become harder to find because of the changes of materials in the newer transmissions. But it's out there.

If you want that trans to shift like butter,go with Redline Mt-90.
It is Gl4 rated,synthetic.Your trans will run cooler and shift like a new car.
I would not use anything else.