gtruck

got a mack renault with a 6sp standard. Any ideas what to use for trany oil?

I found out it's a midliner cs300 vin#VG6BA03BXKB------

Hey guys, I've had this truck for a year now and it has developed a real high pitch whine. Kinda sounds like it's comming from the dif. but not sure. Anyway it's a 1989 300 single axel dump, don't know what size engine with 6sp trany. I think it's the renault model. That's about all I know for sure. It works great but I need to know more about the truck. Thanks