vibrates like your going over rumble strips

Hello,

Sounds like an issue with the drive shaft. There could be a few different reasons why.
The best course of action would be first to do a thorough inspection of the drive shaft.
Inspect the U-joints, the yoke. Also, the mounting point for the drive shaft.
It could be due to any one of those components.

This can also happen due to an imbalanced propeller shaft/drive shaft. Which will vibrate, especially under load.

https://www.2carpros.com/articles/how-to-remove-a-drive-shaft

I have attached diagrams for the drive shaft as well as how to check for imbalanced shaft below.

Please let me know if you have any questions.
Thank you.