2001 ZR blazer, when it's first started in the am and I pull out of the driveway it clunks into first gear. Once it's going down the road its fine and usually done for the rest of the day. Only does it first thing in the morning. Any ideas?

 

Since it only happens once in the morning, my suggestion might not be the issue, but I wanted to suggest it because it is so easy to test. Have you checked the u-joints?