A long time ago, my 86 CRX had a loud cracking noise from the front end, or maybe what you said, a muffled clunk. I cant remeber exactly the sound it was so long ago. Not a bad cv joint sound. I had no idea what it was until the day my front wheel feel off. Not completely off, but you know what i mean. The lower radius arm bearing thing broke. Look and see if your boot is cracked or broken. All the greese comes out and can cause it to fail or break after time.