if u do end up neeing a new trans...drain the new fluid and reuse i

Right, scale of 1-10 how hard is it to rebuild a trans?

Look around in tech info bro IIRC there is a write up somewhere ...if not lmk

I'd start off with a bottle of Lucas stop slip, filter and fresh fluid to top it off (usually about 6 quarts with the Lucas).

I wouldn't recommend reusing the fluid unless the whole trans was drained previously including the converter. Once the fluid mixes, you got dirt etc in there. Fluid is much less expensive than pulling a new trans back out to clean if from some reused fluid.

Rebuilding, I'm more familiar with the 4T65 trans...the younger brother to yours. You'd want a couple of specialized tools, then add in all the upgrades to make it function as good as new, then with the mileage all the seals etc etc. Probably more than a first timer is going to want to do. Might be easier/cheaper to look up car-part.com for the trans and find a nice priced used one.

Alright I guess I should give a full description. When driving with no high acceleration it sounds like its making a low pitched hum, I thought it was just road noise. Along with the light shifting. So start with lucas, filter and fluid.

Yes...

What trans is this? A 4t60? As Bill said, a rebuild is not cost effective because of the tools involved. however, there are options. First, does it go in to 3rd and slip, or not go in to third at all? What happens here will determine the problem. If it'* slipping, then the clutches are gone. If it'* not going in to 3rd then I would drop the pan to do your filter fluid change and take the extra step to pull the shift accumulator. Open that up and inspect the 2-3 piston. Could be a blown O ring which would cause the fluid pressure to not get high enough to engage 3rd.

It goes into third and from what I can tell (amateur knowledge) stays in third but I can barely feel the shift and it feels like it lags. I dont know how bad it is to do this but if I drive semi-manual shifting up at 3000 I watch the rpm drop about 500 and it smooths a bit. by 50+ cruise I'm at 2000

Its not a good idea to do that without installing a manual shift plate....And you are rather hard on your car lol

Ikinda figured that it was bad but thats what my uncle told me to do yesterday to while he was trying to diagnose it, and I am rough on it which is why I want to put a hd in eventually, so it will be able to take it a little but better.