Locker Lube?
 

What's everyone using for gear oil in their 9 inch Detroit locker?

which locker? are you talking about the factory zexel?

Regular Valvoline 75-90 weight. Like recomended. You are not supposed to use synthetic or any additive (Its is not a LSD therefore you do not need it) In fact if you do use synthetic, it will void the warrenty.

You can go to a heavier weight (some say it quiets the locker mechanism down) but I kinda like the clunking LOL.

Since when does the use of synthetic oil void the warrenty of a locker?

https://ls1tech.com/forums/gears-axles/883571-synthetic-oil-note.html

Look at the Eaton's install instuctions on the Detroit Locker. They Specifically tell you NOT to use Synthetic oil.

Thats just a post on a forum. Heres the owners manual for an Eaton Detroit Locker, you tell me where it says the warrenty will be void of you use synthetic.

http://www.eaton.com/ecm/groups/publ.../ct_128312.pdf

You are Right I just called Eaton, They recomend not useing Synthetic but if you do, it will not Void the Warrenty on the Detroit locker.

I have had two lockers in the past and I can not ever remember there being any stipulation in the owners manual. I could understand in an Eaton LSD where theres friction involved between the clutch packs, but for a locker... idunno, i couldnt see it being an issue.