makita lxt drill making a weird grinding noise when i reverse it, is that bad?

A grinding noise when you reverse the drill is a sign of a problem. First, check that you aren't forcing the drill to reverse when the bit is stuck in the material, as that puts severe strain on the tool. If the grinding happens with no bit attached and under no load, there is definitely an internal issue. You should stop using the drill immediately. Continuing to use a tool that is making unusual noises can turn a minor gear problem into major motor damage. A damaged or incorrectly seated accessory, like a driver bit, can also cause noise, so inspect that as well. For any drill that is damaged or making strange sounds, it needs to be serviced by a qualified repair technician using only identical replacement parts.