Diagnosis on Grinding Noise in Engine?

Car: Honda Accord 2004 Lx AUTOMATIC Transmission I-VTECH engine - 4 cylinder

I am the original owner. There is no engine light on.

Alright so when I accelerate quickly (or put strain on the engine, like going up a steep hill was when I first noticed iy), sometimes I hear a light grinding noise and my car does not continue to accelerate. The grinding noise stops in usually under 1 second, and it continues normally. This only happens when the engine is down in first gear (at least that I ve noticed).

Now at first I heard that happen and I thought it could be just a slipping timing belt. But then I realized that the 4 cylinder engine does not have a timing bealt. It has a timing chain. So that doesn t really happen. I also went through and checked the transmission fluid and it seemed to be fine (I guess the AT Fluid pump could be going bad, but I doubt it would run if it was bad). Any ideas as to what this could be precisely? I m trying to diagnose it first before I run it into a mechanic in case I can fix it myself. Any ideas are appreciated. Thanks!

Read more: Diagnosis on Grinding Noise in Engine?