Ariens Rear Tine Rototiller - Drive Transmission Gear Lube?

[MarkF48]

Older Ariens RT5020 rear tine tiller that probably should have the transmission gear lube changed out. I have no idea what the previous owner put in, but it looks milky brown on the dipstick. The Arien's manual specs 'Ariens L-2 Special Gear Lubricant' which is obsolete and any reference I can find is Ariens L-3 synthetic as a replacement which most people are using for snowblower gearboxes and not sure of its easy availability or if it's appropriate for a tiller gearbox. I'm assuming L-2 and L-3 correspond to gear lube numbers GL2 and GL3 and if so, most of what I'm finding is GL5 and a few GL4 gear lubes at typical automotive stores. I'm not even sure what weight would be correct.
Any suggestions???

 

[RustyA]

Would think GL5 80w90 gear lube would work better than what's in there now.