Suspension Issues

I was hearing a clunking sound while driving at low speeds. It sounded like something solid was hitting the floor while driving. I looked under the car and the cv boot was sealed and appeared ok. After doing some research I figured it was the cv axle. However, I wanted to get a second opinon. After leaving my son's football game today I stopped by a car shop. I dropped the car off and walked over to get some food. The mechanic called me over to look at the car while it was lifted and said the cv axle and tie rod were bad. Both boots were split open and grease was all over. I figured I just didnt see the boot from the angle I was looking from earlier (car not lifted and the wheels turned to the left and right). The mechanic said he would charge $600 to repair it. After leaving I didnt hear the clunking noise at all which was very pronounced for the past couple days.

I went home and looked at both cv boots and it was very noticeable from the same angle that I looked at it earlier (car not jacked up and tires turned). I immediately went into a rage and called the mechanic. I honestly think he cut the boot to make it look like it needs to be replaced. He said to see if it is bad he had to turn the wheel when it was lifted in the air and that "probably" pulled the boot out. He also said this issue will mess my transmission up!

Is that true?

Now I am not sure how to proceed. I am not sure if I actually need a tie rod. How do you know if you acutally need a tie rod?

Is there a DIY on the cv axle?