Hypoid Gear Oil GL 4 or 5?

I need to change transfer assembly fluid on my mdx.


Dealer told me to use only (Gear Lube SAE 80W-90 GL4 or GL5)


I've read that GL5 sometimes damages the assembly unit and am little afraid to use it. Acura does not sell this particular fluid/oil and sales person told me that they use regular Castrol fluid (same specs though).


I don't know which one to use. Is there anyone out there who has done this before and had no problems with it?


I appreciate your help.Hypoid Gear Oil GL 4 or 5?
use GL5- as it is the latest specification.