The ranger I'm working on is my best friends. The transmission seems to slip sometimes and bounces when there's no weight on the back. I'm wondering if I need to rebuild the transmission and the rear end or is there something else. I know the shocks are gone. Any advice on this is greatly appreciated thank you and God bless

 

Details like mileage and a general description of condition & maintenance can help.
Do the easiest / cheapest things first.
Just replacing the rear shocks may eliminate the bouncing. You can inspect spring shackles etc.
Dropping the pan & filter changes about half the fluid.
If the ATF is really dirty, you can perform additional drain & fills to get the fluid to near new. Many find this easier and less risky that breaking 25-year-old cooling line connections for a pump out.
There is a band inspection / adjustment you can perform with the pan off.