differential and lunging problems

I have an '07 escape hybrid with a couple of wierd problems I believe are related to the cvt and/or intelligent drive. Only after driving for awhile, the rear end will slip on acceleration, it sounds like the teeth in the differential are not in full contact. It seems to be worse when turning left than when turning right. Could this be a sensor somewhere gone bad, I wouldn't think it's the differential since it doesn't slip at all when cold. Also, sometimes when braking, the truck will lunge, there will be clunk and then it gets smooth again. It doesn't seem to matter if I'm braking hard or soft, it will just happen intermittently. I have searched the forums and have not found anybody having similar problems.