I'm leaning towards conventional. I've never heard of anyone having a problem with a truetrac because of the synthetic,
other than the occasional one wheel peel, and conventional gear oil seems to fix that for them.
I'm taking it now to drop it off, they will be working on it tomorrow. Luckily the guy that runs the shop I'm taking it to has experience working with the quadrasteer axle. I just hope everything goes smooth, wish me luck.