I'm not that familiar with LS tractors, so it's hard for me to tell exactly where it is.
Although Korean tractors are more or less built the same. You can have up to 4 relief valves.
This one, you may have or not. I don't know for sure. But following the high pressure line of the hydraulic pump, it might lead to a block under the tractor just in front of the right rear wheel. This block does have a relief valve and it's where the loader valve will tap into. This is also the main relief since it's the first one after the pump.
Then you'll have the relief valve on the loader valve.
Next there is the relief valve on the remotes valve. Lastly, there is the 3 pt relief valve.
As I said, I'm not familiar with LS, so I just give you the case of my tractor. The order of these valves can be different from what I told and some tractors won't have that block under the tractor.
It's better if you could source a service manual where we could check out the hydraulic diagram first.