Thought I'd bring this thread back to the OP's question and see if I can help.

Zoom, I asked the same question a while back based on a post someone made about the LSD's tendency to "go boom" as someone put it. Apparently, there is something about how they were built that could cause them to fail unless something was replaced. Maybe a search would find more detail on that.

Anyway, I checked the label in my glove box and saw nothing about LSD or anti-spin on the label. I checked my window sticker and LSD is not mentioned there either. Here is a pic of what's in my glove box.



Now, I want to double check, because I am getting ready to service my differentials and read that the LSD requires an additive in the fluid and the non-LSD does not. So, I requested a build sheet from Dodge. The two lines regarding my rear axle on the build sheet are as follows:

DMH 3.92 Rear Axle Ratio
DRBS Corporate 9.25 LD Rear Axle

I googled that second line and found something that stated that "DRB" meant base or basic axle and LD meant "light duty" and a "DRA" would mean anti-spin axle. Now, that was on a forum site somewhere so it could just be some clueless yahoo's opinion. I posted the info here yesterday in another thread, and Weedahoe, who I trust and should know, responded that "DRBS Corporate 9.25 LD Rear Axle" means I do have the LSD rear end. Even though LSD or anti-spin is mentioned nowhere, that I can find, on my truck or in my documentation. Go figure.

 

i haven't run into too many trucks outfitted with 3.92's that weren't LSD... just for whatever that's worth.. I'm not saying they aren't around, but I think maybe they are uncommon..

and the thing about LSD- those dang c-clips.. they sure like to displace themselves.. when that happens, you get tires that bite the inside edge when turning.. which, makes you go sideways if you stiff foot it, just like a locker- no?

i had 3.92's on factory LSD, and bumped to 4.56 on a rebuilt factory LSD.. my rig had 145k on the clock or so before I did it, and the c-clips were a-okay.. I don't abuse the rig in any way though, and never EVER pull bone headed stunts like 'burn-outs' on dry pavement, spins on loose surface transitioning to dry pavement, or any other weird stuff that wreaks havoc on rear diffs, or drive trains in general... I like my feeble transmission too much to stress it when I don't have to..

anyway- the reason I interjected that is this: those c-clips fail, and you have clutches that grab.. and basically have enough power being applied to one side of the axle to get yourself into trouble, but not enough to get yourself out.. it kinda sucks- because an LSD that has broken c-clips bites, but doesn't bite very hard- it loses grip under heavy pressure and behaves like an open diff..

the answer to this is one of those Auburn units.. or another that doesn't have a really weak design.. I say this being kinda funny, because I DON'T have dislodged or mangled c-clips that I know about... when the snow falls, which is rare here, but if it does- that's a really bad time to find out your driving a pseudo locker that doesn't really lock, but bites enough to spin you.. if I lived in a snow prone area, i'd rather be driving a open than a factory LSD, but i'd rather have an auburn over either.. they are predictable..

 

Agreed. It'll only slide sideways if you let it (or make it ). LSD is way better than peg-leg under poor-grip situations.

 

Yeh, Drew, that was the general consensus on this forum back when I was trying to figure out what I had a year or more ago. At that time, I was more concerned about the c-clip issue but now I want to know because of the required additive in the rear end fluid. I thought the build sheet would clear it up but it hasn't seemed to help much, at least as far as making it totally obvious by stating "anti-spin" or "LSD".

Weedahoe says it's a LSD and that's what I'm going with. Sounds like, if you just don't know for sure, it's better to have the additive and not need it than to not have it.

 

LSD and anti-spin are the same thing. It's also called "posi-traction", "Sure-grip", "dual-traction" - probably a few other designations.

 

If you want to check for LSD jack up back of truck. Spin one wheel. If the other wheel spins in the same direction you have LSD. If the other wheel spins in the opposite direction you don't.