    
Bob uk
Unregistered guest
Posted From: 94.197.122.83
| | Posted on Sunday, 23 November, 2014 - 07:19: |    |
The viscosity of gear oils is measured differently from engine oils.
EP 80 has a viscosity of about 20 engine oil. And EP 90 is about 50 engine oil.
So using EP 80w90 GL4 is like using 20/50 in an engine.
GL4 is suitable for stuff with bronze bits in them.
GL5 has an additive that attacks bronze and other copper based alloys.
EP Means extreme pressure and is sometimes called hypoid.
For RR stuff where EP90 is required EP80w90 GL4 is best and is suitable for hypoid gears. It has Zzdp and can be used on new cams.
GL5 and GL6 are for newer stuff and maybe some later RRs.
Castrol do an excellent GL4 synthetic.
(Message approved by david_gore) |