That looks like a TORSEN(tm) diff allright - the worm gears on the diff carrier are a giveaway.  And not being able to turn the wheels independently when turning the wheels.  Those worm gears effectively lock the two half shafts together.  You *might* be able to slow down one of the wheels if you turn the prop shaft instead.
You Lucky Bugger.

From: Stu & Suze []
Sent: Monday, 21 July 2003 5:07 p.m.
To: Supra Club of NZ Mailing List
Subject: [sconz] confuzzled about my diff :s

ok here goes
i have a diff which is definitely lsd buttttttttttt both cv's run the same way and u "cannot" stop one turning.  No it's not welded or else they're the most magnificent invisible welds i've ever seen.  Now it doesn't appear that it's a torson (in a way) coz the cog wheel thingy is no where near the size of John's one (Type R Supra) but heres a few links to some pics i took of it, i would appreciate any enlightenment on this diff :)
Supra Club of New Zealand