I still have not, definitively, determined if I have a LSD in my truck or not. There is nothing on the glove box sticker or the build sheet that seems to clearly match up with what others say would indicate LSD. But, since it seems it would be rare for me not to have it, I am treating it like it does have it.

I picked up some Royal Purple to put in my diff's and it says it is compatible with LS but it doesn't really say it contains a LS additive. So, I picked up some additive as well. Should I just add the indicated amount of additive anyway?

When I get the cover off, is there anything I can look for that would make it painfully obvious as to whether or not I have the LSD?

 

Doubt if the additive will hurt a non-LSD gear set. If "anti-spin..." is not on the sticker, you don't have LSD. A simple test is to put one rear wheel on slippery, one on dry and goose it. If it moves, it has LSD. If not, it's a peg-leg.

 

just add the Slip additive anyways, It wont hurt anything, then it gives you peace of mind. You can buy the additive from dodge, its a small bottle. Where I work, we add one to every dodge just in case, It is always better to be safe instead of sorry.

 

Request a build sheet if anything. That's how I found out I have Anti-Spin

 

The additive in a synthetic fluid will not hurt an open diff.

My rule of thumb: Do not add any additional LSD additive if the fluid already has it. Leave the diff a tad low on the fluid, like the length from the tip of your pinky to the first joint. Put the plug in and immediately go do some tight reverses, a couple real tight circles or figure 8s in both directions. If it binds or ratchets, pop the plug and put 4 oz. of the additive in then if you need to put enough fluid in to take it to the bottom of the hole. If it doesn't, just top it off with the fluid.

In your case where you're not sure if you have the LSD, if no ratchet you either don't have an LSD & haven't put in additional friction modifier you don't need, if you do have LSD and it doesn't ratchet or bind, the additive in the fluid was enough (sometimes it is, sometimes it isn't). If it does ratchet, you'll know for sure you have a LSD...

 

As I said in my original post, I have not been able to determine if I have LSD or not based on the glove box sticker. I have a build sheet and it doesn't make it clear either. See this post and the replies and you can see why I'm still not sure:

https://dodgeforum.com/forum/3rd-gen...or-no-lsd.html

Hammer, I guess that's part of my question - I don't know if the Royal Purple already has the additive in it or not. It just says it's okay for LS axles. I was hoping someone else that has used it might know. I have seen other brands that actually say the additive is in them, but this doesn't state that. Should I really use MOPAR additive or is the tube of LS additive at Advance Auto just as good?

 

I put it in the diffs of my Grand Cherokee, found I needed half the bottle of modifier so it would make tight turns smoothly BUT I have Vari-Lok lockers in both axles which are different from a clutch-plate type LSD. Since I have an Auburn LSD in the rear axle of my truck and Auburn wants conventional oil, I only have RP in the front.

However, from the Royal Purple website:

All viscosities of Max-Gear are formulated with hypoid friction modifiers necessary for use in clutch or cone type differentials. No additional additives are necessary.

 

I see DSA Anti-spin differential in build sheets for those with the Limited Slip.
If that is missing from yours, it didn't come with it from factory.

 

In the link above to the other thread i posted last month it shows what is on my build sheet. However, someone responded in that thread that it means i do have it. With that said, nowhere on my window sticker, glove box tag, or build sheet does anything refer to LSD or anit-spin. I really am starting to believe i have a frankenstein truck built with leftover parts at the end of a production run. My ECM is not stock according to superchips, i didnt have a gasket that the service manual shows i should have, and i may have a rear end that most dont have with my trim and options packages. Nevertheless, its been good to me.

So, is there any easy way for a layman such as myself to tell by looking inside whether or not it is an anti spin diff?

 

Most name brand fully synthetic fluids have friction modifier in them already.
I used Mobil 1 LT which has it. I have never had any issue's of chatter, slippage or bind and I've towed some very heavy loads around very tight turns. I've driven 9kmi this way(mostly local city driving which is the hardest) and never had any issues. There used to be a member on here that would argue you must use Mopar friction modifier. They just buy brand X modifier and slap their name on it, so it's nothing special...

Modifier does increase the breakdown of the oil and dries the seals over time...slightly... Fully synthetic counters this with the anti wear agents and lubrication properties.