I have a 95 ssei. The concern that I have is when the car sits over night and I start it the next morning I get a clunk/knock from the transmission for about a minute. I checked the started and flywheel. im not sure what it is. It drives fine, it just makes a hideous noise that sounds like it is something solid/metal hitting. Any thoughts would help

bmp...

Could be any number of things from a bad axle, internal trans issues or a cracked flywheel.

Can you repeat it by shifting from D to R back and forth? If so..have someone do that while you look for movement in the drive line. Rule out the easily visible things first. Motor mounts, axles, wheel bearings.

this happens before I put it in gear. as soon as I start the engine it makes that noise. it sounds like it is internal. I checked the flywheel as best as I could through the inspection cover. I also checked the starter. so no one has heard of this before?

Are you absolutely sure it'* coming from the tranny? Sounds like you are describing a low end engine knock (crank bearing, lower connecting rod). GM V-motors with high mileage are known to do this, but only on startup, and will run a very long time with this issue. Running a slightly heavier oil viscosity usually quiets this.

I took a long screwdriver and listened. it is coming from the tranny side. :(