I have a loud snapping or cracking sound coming from my front end. It only starts after successive big hits in very rough trails. I checked the frame, headset, all bolts, and suspension pivots. Everything is torqued correctly. I cannot reproduce the sound by manually cycling the fork with reduced or no air pressure.

I let all the air of out and pressurized the fork. The cracking sound was less pronounced but came back. The fork is 18 months old and has about 2500 miles on it. I’m going to go ahead and service the air spring and lowers.

Any other suggestions on what is making the sound?

Nope. A service disassembly will tell you all you need to know.  Good luck!

I had problems with a 36 creaking and popping.  Turns out it was the upper stanchions steer tube. It’s press fit into the stanchions.  Used copious amounts of red locktight around the upper and lower steer tube where it’s pressed in.
It works for a couple months then comes back but I just reapply when I’m done deep cleaning the bike.

I replaced the oil and seals. There was a ton of grease on the air spring. I cleaned it all off and applied slickoleum. I just got back from a ride and couldn’t believe how bad my fork was before. It is so smooth and quiet now.