Oil for 2speed rear axle - EP or not ?

Muncie 4 spds. have bronze sycros. and use GL-5.
CORDially Mike

Thanks for the replies

I did some further research and it appears that not all GL-5 oils are equally corrosive to yellow metals.

So I bought one can of 140W single weight GL-5, dipped a new copper washer in it and will see if the color changes over time, or if I can see some pitting take place on its surface.

I believe bushings E61858 are copper and spacer E61857 is brass.
I use 89-90 hipoid gear lube which can be purchased at NAPA. If you have not gone through the Dual Ratio, I would suggest so, it is the weakest link in the chain.

I use 90W140 GL-5 in my differential. I don't remember any yellow metal in the diff.
CORDially Mike

The technical bulletins keep mentioning to only use a "special" 2speed differential gear oil but not much data is provided on it.

The code in those bulletins has 140EP so I assume that this is 140 weight EP..

Can we use a GL5 EP - extreme pressure - oil with the sulfur additive, or does the axle contain yellow metal parts which would call for a non-EP oil such as a GL1.

Thanks
Rob