Lol, Nailer. Change those fluids! I noticed the biggest difference with the front diff. Motul, all the way.
Anyways, lets have a little refresher on the ATC300, past failures, and weaknesses. Just to get everyone on the same page.
The ATC uses a series of clutches, gears, and servos tied into the DSC system in order to control torque split (max-50:50 to 0:100, f:r resp.).
When the car is turned off, at parking lot speed, or over a set speed, the ATC totally disengages. During normal driving, the ATC sits at roughly a 40:60.
Clutch engagement is controlled in the ATC300 through a servo, attached to a worm gear that in turn controls a cog. That cog then turns a series of gears that control the amount of clutch take up between the front and rear axles.
So, knowing that here are the areas for failure:
-Fluid overheating/limp mode
-Worm gear/cog interface
In my research, the documented failures of x-drive transfer cases seem to all stem from the worm gear/cog interface (x3's, typically). The main reason is that the cog is a plastic gear that isn't intended to take large loads. The secondary reason is that through normal driving, the cog/worm gear will only cycle through a very narrow range. As such, it is my feeling that this is the first point of failure.
Think of it this way: At a hard launch, the ATC must cycle quickly from 0:100 to ~50:50. Since the worm gear is metal and the cog is plastic, I bet the worm gear will strip the teeth off that cog. It's like stripping the head of a screw when you have your drill set at too high of a speed.
But, people need to keep fighting the good fight and bumping up the power until we see transfer cases grenade. Then we know what we are dealing with.
Rule #1 of racing: if you can't afford to break it, you can't afford to race it.
Go: Cobb S2+, Big Tom FMIC, CP-E DP & DCI, Royal Muffler, AR OC
Turn: TC Kline/Swift SA, Vorshlag Plates, UUC Front Bar, H&R M3 Rear Bar, VAC endlinks & spacers, Forgeline 18x9.5/NT05 265 Square
Stop: Endless MX72, Stoptech Rotors/Lines, Motul RBF600