Understanding corolla 4WD system

[NZcelica]

Ok, heres the deal. I have an EL55 corolla II 4WD that has recently started playing up. However this is unlike any other 4wd system, it has a locked centre diff and a viscous coupling halfway along the 3 piece driveshaft.
Oneday I went in a grasskhana and stupidly decided to flick the handbrake up every so often, this resulted in me cooking the centre viscous coupling. Now finding a new one wasn't easy. (TGP is $2300 ) So i managed to find one at a wrecker and put it in...but my car is still FWD not 4WD. So now i'm stumped.
Does anyone know ANYTHING about this weird system and as to why its not working?
Back when it used to work it would spin the front wheels very momentarily until the back kicked in, now it just spins the front wheels (both believe it or not)
The gearbox is a C50F

[sergei]

My guess is that one you have bought is also cooked, unless it is not vscous but electrically activated one....

[RS13]

Ah, the joy of owning a rare car! I'd say the 2nd hand one is knackered too, unless it isn't viscous. Is your car auto or manual?

[Lloyd]

It be manual, the poor little thing

[85AW20v]

Could be the rear diff that is stuffed. Put it up on axle stands and see what turns when.

[NZcelica]

Ah...stupid rare cars, such an awesome wee beast that no ones knows anything about!
Yeah i'm sticking it up on a hoist tomorrow to have a spin of the wheels to see what turns what....and what doesn't...
I'm hoping the new one isnt buggered too!
Would replacing the coupling with a solid shaft have the same effect as "difflock" in the likes of a RAV4?