Context / backstory: I bought this truck (2003 Chevy Silverado 1500 ext cab) and did some work. Replaced brake lines, new battery, etc the easy stuff, but there's two things that are concerning and I don't know what to do to fix it as I don't make much money.

Problem No. 1- Hard asf Shifting. Whenever I shift from 1st to second it's like WHAM! Then second to third is Bang! Third to fourth is just barely noticeable the rest are fine. And as of recently my reverse has been funky aka it doesn't want to move until I get to like 4K RPMs. It's incredibly worrying. It's an automatic transmission btw.

Problem No. 2- idk if this even is a problem but my truck sounds like an airplane and no it's not a wheel bearing unless it still sounding like an airplane in Park when I rev is a wheel bearing. It might just be that my fan is fking loud as Sit, and engine is as quiet as the vacuum of space.

Any sort of tips, info, really just anything to point me in the right direction would be more than helpful.