Been thinking about swapping in a factory 4.11 LSD. Differential into my 1998 Forester .How well do the factory Subaru LSD diffs work? Worth it money wise if spending under $400?

No. All you find in the yard are non functional. The vlsd is prone to malfunction and wouldn't work like you think

If you were thinking of 4 wheelie more, it might be better to do an air locker, so you can use it when you need it, and still be able to drive it normally when you need to. Just a thought. 

Arb makes an airlocker for the subaru?

Edited February 19, 20179 yr by Firemanjim

If i really wanted one I'd do a little more research to verify that they really do fail to open differential - which people have said before.  They tend to be pricey so I wouldn't want to gamble and assume that's what I'm getting. 

IMO, it depends on your definition of "offroad". In some shallow, greasy mud, it might be a decent help. I certainly notice the handling difference in the snow and ice (LSD equipped car oversteers more predictably and will axis spin, I can definitely tell that our Outback VDC doesn't have it), but for real gnarly offroading, it's probably not going to get you much further through an obstacle.

 

 

I've used the comparison for the old-gen clutch type LSD that when you really needed it (lifting a front and a rear wheel), the LSD was like having a couple guys pushing on the back of the car. It's a help, but not a true traction device. And by design a Viscous is going to be even less powerful in that situation than a clutch type....

The viscous rear lsd's are pretty helpless. I wouldn't spend more than $100 for a really low mile one. The clutch type can actually work pretty well, but you have to be abusive with them to get a lot of torque transfer. The harder you hit it, the tighter the clutch pack gets wedged together. They are getting hard to find now though and you would have to adapt the rear axles to fit the male stub axles on the diff.