Possible tranny damage?

Yeah it's a revised manual valve and usually comes with a Trans-go kit. It does allow it to be checked in park but I have seen a few that are a little slow filling the converter back up after it drains down over night so if you just start the engine and check it right away it may be off a little. For that reason I still check them in neutral so I know their reading accurately.

I still agree to check in neutral. But it does at least start to fill in park whereas stock it doesn't fill at all.