You put 3 key words in the same sentence- sharp turn, front wheels pulling, and full time 4WD. Could be symptoms of a bad viscous coupler in xfer case. Bad VC's do not allow slippage and basically lock up the drivetrain when you put the truck into tight turns. My VC was so bad it started plowing by dad's shell driveway when I turned it around. Try doing low speed figure 8's in an empty parking lot to check your VC. If you hear wheels chirping- bad VC. Bad VCs are hard on drivetrain parts, especially CV joints. Your CV joint may be on the way out. If you have busted boots on your joints, replace the axle shafts on both sides. However, consider looking at your VC as well. It could be contributing to premature drivetrain wear.
Was the guy you bought the Jeep from a Jeep enthusiast? I'm not saying that you are at all, but VC's are easily hidden from unscrupulous buyers, and sometimes owners, because the symptoms are not constant. A quick test drive around the block will not sort out a VC coupler problem. Its only in those tighter turns do the symptoms present themselves. Now, if they owner did his research or had the vehicle looked at by a mechanic and the VC was bad, the part is $400 straight up, without labor, and maybe this is how you came to purchase the vehicle? How long have you had it, how long has this popping noise been present and did you get an unusually good deal on the ole ZJ for the mileage?