Ok, this is a 4 cyl, manual transmission. It has recently started
making some kind of grinding noise, similar to a bad rotor, but
intermitent. It only makes this noise while moving forward, under
acceleration. If I push the clutch in a roll down a hill, the noise
stops, the second I release the clutch and accelerate, the noise
starts again. The noise gets faster and louder as speed increases.

I’ve had a couple ideas thrown at me as to the cause, inner cv axles,
and a bad motor mount. I have a sneaky fear it is a bad transmission,
and was hoping to get some opinions before I start throwing money at
it.

Thanks for any help you may offer