Just spoke with an advisor at LE and got this via email:
I spoke with Brian in our Technical Dept. Please read his response below.
“The differentials require a GL-5 and this is not available as 1605 DUOLEC Industrial Lubricant, but it is with our Duolec Vari-Purpose Gear Lubricant. In the 1600 series, we have discontinued manufacturing Vari-Purpose and as supplies run out, they are being replaced and sold as Industrial Lubricant. (non GL-5).”
If you already have our 1604 or 1605 DUOLEC Vari-Purpose Lubricant he can use it.
If you need to buy new 1604 or 1605, it will be DUOLEC Industrial Lubricant. If that is the case, you should not buy it because it is no longer appropriate for car differentials that need GL-5, and we don’t have a straight 90W for him to buy. You will need to use 80W-90, LE 703.
I have attached the product literature below for your review. Please let me know if you have any questions.https://www.lelubricants.com/lit/flyers/0703-0704%20Product%20Info.pdf