Ok, I have a 46 Chevy 1/2 ton pickup 4 sp tranny. I’m changing the transmission oil and have been told to use Gl4 80w90 oil that doesn’t contain sulfur and phosphorus, and not Gl5 because it will damage bronze and copper. The problem is I can’t find GL4 anywhere, tried all the parts stores. What I do find is some that are for GL4 and GL5 applications. My concern is does this contain sulfur and phosphorus? It doesn’t list ingredients on the bottle. Anybody know if this will be safe for my 46 transmission?