Gear oil question

I'm looking for a recommendation on what gear oil (brand,weight) I should use in my front and rear diff.

Also the front diff has the LS tag on it but when I raise the wheels off the ground and spin them they spin in opposite directions. May not have limited slip or possibly out of adjustment? Would it hurt to put the additive in anyway?

Rear wheels do both spin the same direction when raised.
I think that it probably has factory Power-Lok but has no tag. According to the owner's manuel the Power-lok diff would have the ls tag.

It could be possible that the tag got put back on the wrong cover....................but what kind of bonehead...............

Someone got a picture of what I can expect to see if it a power-lok and one of an open diff?

Thanks!

 

if you remove the fill plugs, the powerlock case will be right there; you won't be able to put your finger in very far; you can see the case easily thru the opening.
If an open diff, you won't see much; lot's of room to poke into.
in my opinion, only the rear diff needs the additive, because you are driving on it all the time; it gets warm, it might chatter around corners without the additive; the front only see use in 4wd.

 

Thanks Jim.
I opened them up and found I had a powerlock front and back.
The front now spins both tires the same direction when off the ground.
I did some 4-wheeling earlier today (very impressed) and maybe it just needed to be used after all that time?

As far as the additve goes.........I bought one tube and it will go in the back.
I attached a couple pics........don't bag on my RTV job, let's just hope it doesn't leak

 

impressed i would be,with that setup you should be able to go just about anywhere,also would put the additave in the front also it wont hurt anything