Klunking Noise

Hello All...Happy New Year!!!
I have a 1988 2.8 L 4x4 S-10 Chevy Blazer with automatic transmission. The problem is that when I start the truck there is a clunking noise coming from under the car, like there is something hitting something else. It will do that as long as the car is on and idling. When you are running the truck, it used to go away, but not anymore althoug is not as loud. I thought that the engine went bad, but is not coming from the engine. it's somewhere between the engine and transmission. Could it be the flywheel? If it is the flywheel, can that get loose by itself? If it is loose, will I be able to tight it w/o having to get the trans out? Any help and ideas you provide will be appreciated. Thank you guys!

Depends If It's A Loud Clunking You Could Have Something That Has Broke Off Or May Just Be Un Ballanced, Could Be A Flywheel, Check The Starter Also, But The Flywheel Could Come Loose If It Wasn't Properly Installed It Is Only 5-6 Bolts With Lock Washers, Never The Less...
Get It Checked Out Before Your Replacing An Entire Engine/transmission Because Of A $100 Part. Good Luck

It likely is your torque converter which you will have to move the tranny back in order to remove, but first thing you should do is remove the bellhousing cover and check the flywheel bolts, there are 3 of them (i think) and they are a 15mm wrench size. Check those, if they are tight then it is probly your torque converter. If that is the case you can probly do it yourself because the torque converter just slides onto the tranny spline shaft, no tools required. Hope that helped.