1998 Blazer Strange noise in drive

I have a 98 Blazer when in drive setting still and going down the road makes a metal scraping sound or similar to vac leak sound. Sounds like center of dash around hump in car.
When you put it in reverse the sound stops completely. Truck shifts fine.

Any info would be appreciated :banghead:

possible that the torque converter is showing signs of failing?

Did you check the fluid level at warm idle after shifting into every gear then returning to park?

Yes checked fluid making sure it was hot. Converter seems to lock up fine also. I serviced trans fluid and filter and there was very little crap in pan.

:banghead:

Does it sound like a pinging? The transfer case is chain driven and I believe a sealed unit. Mine is doing it too but Im so done with it Im just beating it till it dies