Imminent signs of transmission failure:
1) Difficulty shifting
2) Gears out of mesh sound (Too Late)
3) When changing oil you see a silver color or metal flake in the oil. The oil can be black but NO silver color in the catch can.
CO

I need to change my oil. Haven’t done it this year yet.

Difficulty shifting, indeed... I never wanted to have to get intimate with a tranny :(
To clarify, do you mean difficulty shifting into gear from a standstill?

Yes

CO

Edit: I'm not talking about the occasional grind as it's going into gear.
That happens when you don't let the rpm drop way down.
I'm talking about it being almost impossible to get into gear at a standstill.
If you're not sure remove the cable assembly from the transmission and make sure it's not your cables by moving the shifter. If everything is fine then it's your trans - you're screwed.
CO