eneos en-gear 75w90
 

gl5 but a good price and looks like it meets the requirements. any thoughts. not a fluids expert here.

btw the motul i see everyone using is also gl5.

Motul is GL5 AND GL4


Anything that is ONLY GL5, can only be used on the Diff, but NOT in the tranny. Anything for the tranny has to be GL3 or GL4 or GL5 and GL4.

in the tranny? no. what about cST guys? additive packs? gl4? see my pentosin thread for tranny oil guidance, on pg 11 there are others if you prefer other than pentosin
we all have our reasons for choosing our fluids...

as for the eneos en-gear in the rear diff, why not? prolly good stuff

Typical Properties
SAE viscosity grade 75W-90
Density (20°C), g/cm3 0.8834
Flash point (COC), °C 204
Kinematic viscosity (40°C), mm2/s 79.9
(100°C), mm2/s 14.6
Viscosity index 192
Pour point, °C –42.0

I would try to stay with pure GL-4 fluid. GL-5 fluid has extreme-pressure additives which are designed for differentials and not transmissions. A GL-5 fluid can meet GL-4 specs for not corroding soft metals, but it still has additives that are not necessary or preferred in a manual transmission.

That ENEOS GL-5 should work just fine for the rear diff, although probably any GL-5 would.