Is the cherokee in 4 wheel drive when it does this? Sounds like you need to check the transfer case and differential fluids to me, they may be low which will cause massive damage if you drive it that way too much. The turning issue sounds like it is in 4 wheel drive, as the front tires will definitely grab and jerk the vehicle when turning. Check your fluids and make sure you aren't driving in 4 wheel unless you need it.
