Hi Roger
I haven't had the car out yet after changing to 75w90 GL4. (This is not California weather up here in the great white north!!!!) I'm going to drive it without the additive first and see how it shifts. If it still clashes, then I'll add the Lube Gard. I've left room to add the whole bottle.
Jim
Thanks Jim. When you get it out, let me know how the 75w-90 works. I'll add the rest of the bottle and see what happens. I know what the great white north is like. I lived in Michigan for 39 years! Roger