Is it normal for my skid steer to start clicking when it's under load?

That clicking under load is a textbook sign that your **final drive** is starting to chew itself up. It’s usually a carrier bearing or a planetary gear losing a tooth, and the reason it only happens when you’re pushing or turning is becuase that’s when you’re putting the maximum torque through those components. Your foreman is playing a dangerous game by relying on the computer. These mechanical assemblies don't always have sensors to throw a code untill the thing literally seizes up or blows a seal.

You need to pull the drain plug on that final drive as soon as you can and look at the oil. If it comes out looking like metallic flake paint or has actual chunks of "glitter" in it, that machine needs to be sidelined immediately. I’ve seen guys ignore that sound for a week only to have the drive motor lock up completely in the middle of a pile, and then you’re stuck trying to drag a dead machine onto a trailer with a locked track. It's a nightmare for everyone on site. And check the mounting bolts while you're at it. Sometimes a rhythmic click is just a couple of **sprocket bolts** that have stretched or snapped, allowing the sprocket to shift just a hair under pressure. If you see shiny metal around the bolt heads or, worse, find a bolt lying in the dirt after you move, there’s your answer. It's way more common than you'd think for those to work loose during heavy grading. Waiting for a "real" sign usually means waiting for a catastrophic failure that costs three times as much to fix. If it's loud enough for you to hear it over the engine and through your cab, it's already failing. Better to lose a day of production now than two weeks later because you had to replace the entire drive assembly instead of just a bearing.

I went trough this with my T650 last summer. I was convinced the planetary was toasted, but it ended up being way simpler. My track tensioner was slowly bleeding off pressure. Every time I’d bite into a heavy load, the track got just loose enugh to slap the frame or jump a tooth on the sprocket. It sounds exactly like a metallic click. Check your tensioner piston and see if it’s leaking grease. If you're pumping it up every day just to keep it tight, there's your noise. Way cheaper fix than a drive motor if that's all it is.

Have you ruled out a bad bottom roller yet? Everyone jumps to the final drive becasue it's the expensive nightmare, but a seized roller or a flat spot on one of the wheels will click rhythmically once you put weight on it during a turn or a heavy push. I'd crawl under there and see if any of them feel significantly hotter than the others after you've been working the pile for an hour. If one is burning up while the rest are just warm, you might just have a bearing failure in the undercarriage rather than the drive motor itself.

Update: I crawled under there like suggested and found a seized bottom roller. It had a nasty flat spot that clicked every time it rotated under a heavy load. Replaced it this morning and she’s back to running quiet. realy glad it wasn't the planetary gears chewing themselves up. Thanks for the help, saved me a massive headache with the foreman!