Torque bias posi unit?
 

In a torque biasing posi unit. Should both wheels turn the same way when turned by hand (on jack stands).
I know that with a regular posi both wheels will turn together. With an open differential one wheel turns one way the other will turn the opposite.
This is a front wheel drive car but I'm pretty sure it works in the same way a rear drive differential works. The torque bias stuff is new to me though.

Re: Torque bias posi unit?
 

I think if it is a Torsen then if both wheels are off the ground, and you turn one, the other will go backwards. You need to put torque to the input to get the gear train to lock up. Then depending on the bias, if one wheel loses traction it will go back into wheel spin.