Not true. Thor was mysteriously absent during WWH, and when he came back he had the full power of Odin- a massive power up. If you think any version of hulk is on Odin's level (and that's obliterating galaxies, smashing moons to dust, fighting across all existence simultaneously) you might want to rethink that. All-Father Thor took out the destroyer in one shot. There was also a really cool story with a Thor in the grips of warrior madness beating the hell out of Drax with a power gem and claiming it for himself, which is a really great story. (short version- no one can stop him, so they intentionally drag Thanos into it hoping he's the only one that can put down an enraged Thor. Thanos then goes toe to toe with Odin(!) )
Regardless, Defenders 10 is a good example of the hulk/thor relationship- marvel tends to put them on equal footing. There's also similar instances with Hulk vs. Juggernaut, Thor vs. Hercules, and Red Hulk is currently fighting the juggernaut version of colossus. That tier tends to get kind of hazy and basically comes down to who is having a better day.
Of course Thor coming at Hulk with his daddy's stroke is a different story. When it is just regular Thor, it is usually his hammer that saves him.