I've seen the dark side and held it in my hand

["Lawson, Dave" <dlawson@ball.com>]

I have my 1990 200 TQ avant in the shop getting the clutch replaced. Every 
conceivable part I can think of associated with tranny removal is being 
replaced including pressure plate, clutch disk, throwout bearing, pilot
bearing,
crankshaft rear main seal, flywheel bolts, tranny input shaft seal, metal
throwout bearing sleeve, clutch slave cylinder, left and right output flange

seals, rear center driveshaft seal, clutch master cylinder and clutch pedal.
I was looking over the progress today and the owner asks if I want to check 
out my T*rsen differential. They removed the differential because the
bearing
the rear output shaft rides on was not perfect and has some 'roughness'
when rotating. Now this is nothing like the almost totally siezed throwout 
bearing, but just didn't have a smooth feeling.

Anyways the T*orsen was just pulled out the from the rear of the case. It 
has interesting manufacturing marks, the surfaces of the gear teeth appear 
to have small ribs. You could see where the gears mesh because these 
surfaces were worn almost smooth. BTW this example has about 140k miles
on it. The side gears also show this ribed surface. The gears were easy to
spin 
with the tip of a finger. 

I didn't see how the t*orsen was removed, but looks pretty straight forward.
The replaceable items that I know of are the rear output flange seal, an
o-ring for 
the end of the case where it mates to the cast case and the bearing the
shaft 
rides on. I did see a few circlips around which must hold things in place.
I'm
not sure what difference the bearing will make, but they didn't like the way
it
was performing it's duties and dug right in to replace it. So replacing this
bearing
might be on the list for other t*rsen owners who want to service their
'lifetime'
center differential. I asked about any t*rsen failures, and he only new
about 1, 
which was in the rear diff of a 300ZX world challenge car.

If anyone is wondering, the work is being performed at Slipstream Autosport
in Boulder, Colorado, a very performance minded, Audi friendly shop. Many 
employees drive Audis, including 91 200 wagons, a few IT race cars around
etc.
They are installing a 4WD dyno into a bay for performance testing and it
should
be online sometime this fall.
-
Dave Lawson
1990 200 TQ avant
1983 ur-q