2005 JCB 214 Transmission question

I recently purchased a 2005 JCB 214 backhoe / loader. Since the lights weren't working, I started looking at the wiring. I found a loose connector in the side dash, and plugged it in. Now there's a warning light on (looks like a gear with a drop of oil in the middle). I think this is the low transmission oil warning light. I changed the transmission fluid, and the warning light is still on. The backhoe drives forward/reverse as is should (as best as I can tell.) The transmission is a 4 speed, and there's a lever on the steering column to change it between F, N, R.

Any thoughts on why the warning light is on, and what I should check next to fix it? Does anyone know where the sensor is that reads the transmission pressure level?

2005 JCB 214 Transmission question