Limited slip diff

[cloker12]

Getting ready to tow south for the winter and have done some upgrades on my truck this summer but i am thinking of changing out my rear diff oil on my Dana 80 and am wondering #1 if it is a limited slip or how you go about finding out if it is and # 2 what type of additive can be used and how much.

 

[DavidC]

If you use standard gear oil you will need a friction modifier. I use Royal Purple which does not need the additive and there may be others. I know this use to be discussed here years ago.

Dave

 

[DavidC]

https://www.turbodieselregister.com...n-modifier-already-added.258802/#post-2511861

Dave

 

[BarryG]

I used amsoil in my 01 diffs and never needed the additive
If you cant figure out if you have LS jack up the rear end of the truck spin one wheel if the other wheel spins the opposite direction it is an open diff it it spins same direction you have limited slip and as David said if just standard gear oily will need the additive

 

[KATOOM]

Getting ready to tow south for the winter and have done some upgrades on my truck this summer but i am thinking of changing out my rear diff oil on my Dana 80 and am wondering #1 if it is a limited slip or how you go about finding out if it is and # 2 what type of additive can be used and how much.

Sometimes there's a build sticker on the inside of the glovebox door. If its there and still readable then it will tell you if there's a LS differential.
Or you can jack the rear axle off the ground. With the e-brake off and transmission in neutral, spin one tire by hand and see what the other tire does. If it spins in the same direction then you have a LS, but if it spins in the opposite direction then its not.

If you use a synthetic fluid then likely friction modifier is already included in the recipe. Not always enough though so if the differential chatters during turns when its fully warmed then you'll need to add more friction modifier.

 

[Bill Lins]

Sometimes there's a build sticker on the inside of the glovebox door. If its there and still readable then it will tell you if there's a LS differential.

On my truck (early 98) the sticker is on the underside of the hood near the front edge.

 

[PBJ2500CTD]

Depending on the year of your truck you can check the truck's build information by entering your VIN number in the "Your Vehicle - Equipment Listing" on the RAM Trucks website https://www.ramtrucks.com/webselfservice/ram/index.html?screenName=customer&country=us&emailUrl=goToEmailForm%28%27R%27%29

 

[Cummins12V98]

Personally I would use AMZ/OIL 75-110 SevereGear. They say no SlipLoc is needed!

 

[cloker12]

Thanks everyone for your replies.
I will be checking the diff out and go according to the info you all have given me.

 

[Bill Lins]

Personally I would use AMZ/OIL 75-110 SevereGear. They say no SlipLoc is needed!

That's what I use & I've never had to add friction modifier.

 

[NIsaacs]

Thanks everyone for your replies.
I will be checking the diff out and go according to the info you all have given me.

If you want to buy the oil prior to pulling the cover, just get the oil with the additive in it, it will be fine in an open diff. Top picture is open, bottom is limited slip.