Sounds like the inside of the CV axle is worn out. I can't think of anything inside the disconnect that would clunk like that.
If you pull the CV axle, it would be a good idea to remove the disconnect, and disassemble, clean, and re-grease it.
The disconnect is bolted to the oil pan with 4 bolts. I'm going to assume you already have the vehicle up on jack-stands. Get underneath and remove the 4 bolts holding the plastic "skid plate" on. Once that's remove you have clear access to the rear of the disconnect.
The disconnect will be corrosion bonded to the oil pan. If you try and just pry it there is a high likelihood that you will break the disconnect and leave the back half stuck in the oil pan.
What you want to do is use a plastic or rubber hammer and tap the bottom of the disconnect, on one side or the other, straight up towards the hood of the car, not out towards the fender. You won't be able to go very far with it, maybe 1/2" or so. Then tap the other side in the same manner. Do this 2-3 times. What you are doing is breaking the corrosion bond between the disconnect and the oil pan.
NOW tap the back of the disconnect out towards the fender, just a little bit. Then tap on the front and drive it back towards the oil pan. Repeat this process, going a little farther each time, and the disconnect should come out without any damage.
Here's a good article on rebuilding or servicing the disconnect. If you find damaged parts, use the part number in the article to find replacements. They are still available.
offroadtb.com
When I replaced mine this past fall, I knew I was going to be replacing the CV axle, so I just used an angle grinder with a cut-off wheel and cut the axle shaft in half. Then I used a bench vise, a steel drift punch, and a 3 lb. sledge hammer and drove the stub out of the disconnect. If your axle won't come out of the disconnect, that may be what you need to do.
If you pull the CV axle, it would be a good idea to remove the disconnect, and disassemble, clean, and re-grease it.
The disconnect is bolted to the oil pan with 4 bolts. I'm going to assume you already have the vehicle up on jack-stands. Get underneath and remove the 4 bolts holding the plastic "skid plate" on. Once that's remove you have clear access to the rear of the disconnect.
The disconnect will be corrosion bonded to the oil pan. If you try and just pry it there is a high likelihood that you will break the disconnect and leave the back half stuck in the oil pan.
What you want to do is use a plastic or rubber hammer and tap the bottom of the disconnect, on one side or the other, straight up towards the hood of the car, not out towards the fender. You won't be able to go very far with it, maybe 1/2" or so. Then tap the other side in the same manner. Do this 2-3 times. What you are doing is breaking the corrosion bond between the disconnect and the oil pan.
NOW tap the back of the disconnect out towards the fender, just a little bit. Then tap on the front and drive it back towards the oil pan. Repeat this process, going a little farther each time, and the disconnect should come out without any damage.
Here's a good article on rebuilding or servicing the disconnect. If you find damaged parts, use the part number in the article to find replacements. They are still available.
Front Axle 4WD Disconnect Rebuild | offroadTB.com

When I replaced mine this past fall, I knew I was going to be replacing the CV axle, so I just used an angle grinder with a cut-off wheel and cut the axle shaft in half. Then I used a bench vise, a steel drift punch, and a 3 lb. sledge hammer and drove the stub out of the disconnect. If your axle won't come out of the disconnect, that may be what you need to do.