I have a 97 Blazer 2dr and its not a 4X4.. everytime i shift from park to drive it makes a big clunk noise.. also when i start to pull away from a stop it makes this rele loud noise like a slashing sound then goes away ones im up to speed.. i dont know what it is but my best guess is that its the u joints.. if any1 knows plz help!!

 

if it was a clunk when shifting it would be a trans mount...
from the sound you describe that definately sounds like u-joints, and it sounds like theyre BAD. i'd get that taken care of ASAP.

 

also when im in park then shift to drive then to reverse u can see the pinoin rotate without the truck moving.. thats when the clunk acures.. is it play in the pinion gear and ring.. also is it repairable to do myself..?? help!

 

You're going to have some rotation of the driveshaft due to the fact that there is some play built in to the transmission, and differential. When you add up the play in both you'll see that in the driveshaft as all play combined.

You might want to check that the yolk on the rear differential is tight. If the splines are worn then it would have exessive play and possibly cause a clunk.
Another thing to check is worn universal joints or a loose pinion nut.

So there's a couple of ideas to look at.
Hope this helps

 

if the pinion nut is loose you can try tightening it but usually if it gets that bad youve done damage to parts in the rear.

 

I remember that sound well, it started off low then gradually got louder over a period of a couple months ... It was my rear U joint.