ok so i just got off the phone with champion. they provided me with all the options the car has.
the car does NOT have code 220 on it.
a locking rear axle IS a mechanical LSD. it is not software. its a real LSD. atleast I learned something today

I guess good news otherwise factory left it out, I'm sure it happens.

Okay so then us TT guys are prone to the same failures as the GT guys.
I hear the OEM unit is weak typically upgraded with a Guards unit.

BOB- why does the method for checking Axle diff lock not work on a TT?

yes i'de bet if you drive your car halfway aggressively, your LSD is toast.
i went with a motorsport diff
the guard diff uses the same ramps as the motorsport diff.

bob was saying that with the awd, you wouldnt be able to make one wheel move because it would make the front wheels move, but i dont think this is the case because the front drive is all electronic.

Chris,

Nothing is wrong with the tranny, i wanted different gears so i had to swap the entire unit.
as a matter of fact, the 997 tranny was FLAWLESS. gears, bearing, sliders, IMS, synchros. everything.

the only thing that was pretty worn was the clutch fork.
tranny has 55k miles, and the previous owner (6speeder) took it to the 1/4 mile.

I just had a Carbonetics LSD put in my 997TT car, which did not have a LSD previously. While the car was up on the lift they were spinning the rear wheels and the front wheels did not spin with them. Apparently this is not the case with the 996.

how are you liking your carbonetics ?
what kind of power are you making ?

I have to admit I haven't had a chance to test it much yet. Just had a motor rebuild and just finished my 1000 mile break in. Is actually in the shop and getting dyno tuned right now. Should be making in the neighborhood of 600-650whp. Basically, I have the EVT700 kit plus a 3.8L piston/cyl kit.

So far, I haven't noticed any noise at all though. Very quiet and smooth.

Tom, not an expert here, just what I think :-) I know:

PTM controls the Center Differential, distributing power between front and rear axle.
In 996 Turbo this is a viscous multi-disk clutch, in 997 Turbo it is electronics multi-disk clutch. The control of 997, unlike 996 which works by response to front/rear speed difference, is electronics. Sensors sense individual wheel speed, whether driver is driving like a bad boy (lateral and longitudinal accel.), then control the plates to make the car become more rear wheel biased in aggressive driving, more front biased in other situations, etc. It is I guess an elector-mechanical system. The actual application is mechanical by way of disks, but the control of these disks is electronically.

BTW, PTM was changed between 997.1 and 997.2; 997.2 is more rear-biased for less understeer, more fun. The adjustment for 997.2 unfortunately cannot be applied to 997.1.

The $500 LSD option as we all already know is referring to the Rear Differential. I have a headache every time I try to understand how it works , so I'll stop here. I don't understand how the above 2 differentials apply to the wheel lift test Bob mentioned either; I am lost for now :-).

I think the test still works bc you're testing the mechanical component of the system with the car off in neutral.
I just did the test on my sub 10k car, lots of resistance.
Steve, another option is the motorsports clutch pack.
Pics of the car?

Okay thats great news Chris.

Can--- from this simple analysis we can assume it's not em controlled or torque biased rather a true mech-LSD.

Not bad for such a cheap option.

I'll run the same test on mine next week when I get a few things installed... teaser attached. Should have not met VID997 at the bar hes costing me money already and not just drinks.

chris,
i bought the car two weeks ago, and still havent taken delivery.
here is a pic the previous owner sent me.
btw, yes i am going with motorsport clutch pack. another option for guys with the lsd already installed is to just switch out the clutch packs to motorsport and all systems are a go !
this isnt what she's going to look like when i take delivery, the gt3 wheels are being repainted to look like oem gt2 - 2 tone wheels.

i should be picking the car up next saturday.

every hour feels like a day.

The test for mechanical LSD that I've used on my 964s and 993 is as follows:

Both rear wheels have to be off the ground with the E-brake disengaged.
Spin one of the wheels.
If the other wheel spins in the same direction you have a working LSD.
If the other wheel spins in the opposite direction you have a worn LSD or an open diff.

Shouldn't be any different in the 997TT.

thats true, but not 100% true..

it doesnt take a lot of preload to spin both wheels when the car is off the ground

meaning, if youre making lets say.... 700lb ft of torque, doing the lsd test will not tell you if your lsd is still an lsd at 700lb ft of torque.

theres a thread int he gt3 section that explains in detail how to check your OEM LSD