Neat animation of torsen differential.

[user removed]

locker without clutches.

https://www.youtube.com/watch?v=JEiSTzK-A2A

regards
mech

[oil pan 4]

At one time you could buy a used/takeoff Zexel-torsen for GM 7.5'' and 7-5/8'' 10 bolt rears for around $100.

Detroit lockers don't use clutches.

The bad thing about clutched posi units is they can wear out as soon as 50k miles.

[redpoint5]

Why would anyone implement a clutched posi when this tech exists? No friction plates to wear out and instant response. There must be a drawback. Expense? Fuel economy?

[oil pan 4]

The problem with any kind of posi or limited slip is winter.
The instant on you get with a Detroit locker and some of these other geared units will spin you around. The clutched units engage a little gentler but give you the same result.

I say go with something that can be externally turned on/off and more importantly locked out for winter/ice time operation. Something like the elocker that Toyota uses or the relatively new ARB air locker. Leave it off and it functions as normal one wheel squeal OEM open diff. Engage the locker and it becomes a spool. Since it stays off most of the time to start with and fully locks and unlocks, not slipping between on and off cycles, it cant really wear out.

Putting a diff that acts like an open diff on road and then becomes a spool when you need it that would greatly reduce the amount of damage vehicles do when they go off onto soft ground.

[RedDevil]

+1. The Torsen differential does cause some friction going through corners, more so than a conventional diff would.
ABS, stability control and the like can deal with loss of traction in a controlled way.

But my Insight does have a way to switch VSC off to free itself when locked in snow or something. I thought the system would help, not hurt, in such situations, but apparently not.
Using winter tires I never had to do switch it off, not even in 10 inches of snow.

[niky]

Love these things. Only issue is that they don't work if you've got a tire in the air. Which, if you're going off-road, happens fairly often.

But a helical LSD almost always improves the driving experience.

[oil pan 4]

So far on every vehicle with traction control I have used on snow and ice, the traction control makes the vehicle easier to get stuck and more difficult to get free.

The ones that with traction control that do the best on snow and ice, have traction control that you can fully turn off.
The ones that do the worse, like our VW, have a switch that "turns the traction control off", but it really just makes the traction control a little less active.