Have you checked to make sure that your tires are not hitting/binding on the frame when at full lock?
If not that then the only thing I can think of that might cause those symthems only at full lock would be the CV's...possibly the retaining ring was left off the joint during a boot replacement or aftermarket shafts that are slightly shorter allowing them to pull out during full lock turns.


TCase and tranny shouldn't be affected by turning...if it were one of those it seems your symthems would accur at other times also.