The opening credits show the Hulk picking up a car and rolling it down the hill. This was not a special effect. When they were filming the scene, the steel cable that was supposed to help Lou Ferrigno lift the car broke. It was 4 AM, cold, wet and Ferrigno had been working 18 hour days to refilm all the Hulk scenes for the pilot (the role had originally been played by Richard Kiel). Ferrigno was so frustrated that he decided to lift the car himself rather than wait for the special effects team to try to reset the cable.
Lou Ferrigno was the only actor to appear in every episode. Bill Bixby was forced to miss one episode due to court hearings relating to a messy divorce he was going through. Banner appeared very briefly with no dialogue in the episode and was portrayed by Bixby's stunt double. Jack McGee does not appear in Never Give a Trucker an Even Break (1978)(#1.9), Killer Instinct (1978)(#2.8), 747 (1978), Like a Brother (1979), or Fast Lane (1981)(#4.3).
When the TV series was on the air, Bill Bixby was very careful never to be photographed with Lou Ferrigno in his Hulk makeup because he felt for photos to get out of the two of them together would destroy the illusion to children and fans of the show that they were not the same person. The tabloids of that era were always trying to get a picture of David Banner and the Hulk creature together but were unable to do so.
Lou Ferrigno had been an avid fan of the Hulk comic book series well before becoming involved in the TV series. Ferrigno has often credited the Hulk character in helping to inspire him to help overcome the difficulties he faced related to his hearing disability and other personal issues.
At one point, a cost-cutting move was proposed to eliminate the Jack McGee character. Bill Bixby and Lou Ferrigno both said that if that happened, they would walk off in protest as a show of loyalty and support for actor Jack Colvin.