Grindingish noise when slightly accelerating around 40MPH

I have a 97 honda accord and recently have been hearing a grinding/low humming noise and have felt very slight difference in drive feel. This issue happens when i have the car mph near 40 and slightly hit the accelerator. When i release the accelerator the noise stops, if i increase the acceleration the noise stops. I also can keep the noise going for a bit if i keep my foot at the right spot. I did check the transmission fluid which it was a clear brown but didnt smell burnt. I dont believe this is related because there hasnt been any clicking or gear slips at all but felt i should add it. 4cyl automatic

Is this a noise only, or do also feel vibration?

Regardless of whether or not it is related, brown transmission fluid is very bad. If you want to up the odds that this car will continue going, you should have it serviced including a pan drop, new filter and complete fluid exchange (not a “flush”) - make sure only the Honda recommended fluid is used.

agreed, Im bringing my car in tomorrow to get the transmission fluid drained and replaced and a new filter. My mechanic is also gonna check this issue with the grinding as well. But im impatient and wanted to see if someone had an idea of what it was. So far ive seen:

cv joint, bearings, exhaust rattle (multiple parts could be this cause), and torque converter.

Im personally leaning towards the rattle, because the is no sound when i turn the wheels and yes the trans fluid was brown but wasnt burnt. (the was a grandmas car and she didnt change anything in it, the place i bought it from was supposed to put new fluid in but im doubting they did, and seeing it has now hit the 120k milage mark the trans fluid has just gone bad)

The issue is only noise

My gut feel is that this is a torque converter issue, based on some very similar descriptions from people with the troublesome Honda and Acura transmissions that came out a few years after yours.