afoulk

My truck has the factory limited slip rear with 3.55's (Dana 80, srw). It hasn't seemed to work right since I bought the truck. When it rains, I can't get the back end to kick out at all. It just sits there and spins like only one wheel is getting the power. But if I jack it up and spin one wheel, the other wheel spins the same direction. I did change the oil about 5,000miles ago and used Royal Purple 75w-90 which already has the limited slip additive in it. So, I'm guessing my LSD is either shot or something broken. Anyone know who makes an aftermarket unit for my rear and wheres the best place to get one?

bigdav160

Sounds like its working.

Do a search. There's a few good threads on how to tighten it up.

PaulDaisy

The FSM has the torque specs for checking the force required to spin the LSD clutches. Maybe someone with a FSM handy can give the numbers to you?
-P

Need95-00CTD

I know you just changed the fluid, but next time run it without LSD additive, it will tighten it up a lot, and you may even get the typical chatter of a locker or spool. If that happens put in a little additive and do a figure 8, if it still chatters too much, add a little more and so on, that will really work wonders for them. One of my problems with Royal Purple and LSD's is that since they are such a good lubricant, clutches will not grab or stick to one another well at all when you use it, its great for the gear-set and may add a bit of HP, but the LSD becomes worthless with it. I had to test all sorts of diff fluids when I worked my last job, and these are real world bench tests, not just chemical analysis.

afoulk

yeah, but if I add lsd additive, that'll just make it worse wont it? doesn't the additive cause the clutches to slip even more? what gear oil have you found to work best? also, I found a couple posts on hear that mentioned taking clutchs out and switching them around, but I think that was only for the power loc, or what ever its called. Is there anyway to tighten mine up, or should I just try a different kind of oil.

Stamey

If you decide to rebuild it, installing new clutches, Randys Ring & Pinion is probably the best place to get it from. Their pricing is quite reasonable. You can get just the clutches and steels, or the entire guts of the LS unit.
You almost certainly have a powr-lok in that rear. I have not heard of any Dodges with Danas that did not have the Powr-lok id they have an LS rear.
I can say nothing but good about them, as I have one in each of my trucks, and the 96 is still tight, even after 219K.
I am running Amsoil, and find I need to add FM to reduce the chatter.
If you decide to go with something else, the Detroit Locker is good, but not all that street friendly. The ARB air/electric locker is the best, because you can lock it at will, with a switch. It's also the most expensive.
The EZ-locker, essentially a bargain locker that will replace the guts on an open diff, is not a good choice for these trucks, due to the torque output of the engine. They just can't hang with the torque. This will also be less street-friendly than the Powr-lok.

Chris

SIXSLUG

Mine is doing the same thing w/ the royal purp 75-90 with friction modifier already in it. I got stuck Tues going up a dirt driveway and couldn't get the LSD to kick in. I jacked it up and both wheels spin forward if I hand turn one. I think I'll drain it and try the Amsoil w/ no fric mod and add a liitle as necessary.

afoulk

which amsoil stuff should I try? the severe duty stuff?

SIXSLUG

I haven't looked into it yet but if you do a search on diff fluids you might find what the others are usin and some informed opinions. I just don't get stuck very often so the change will be kind of low priority while its still warm and dry around here. The amsoil stuff isn't cheap!