So I knew I had a problem with my front drive shaft where it goes into the front axle.. tons of play in it and a bad transfer case. Mechanic told me it os stuck in 4lo and the front drive shaft is constantly spinning but front axle is not engaging. So today I took out my 4 wheeler and put truck in the mud and now I have a bad wobble when I try to drive at a steady speed mainly over 40. Not when I swamp it and it shifts to accelerate but mainly when I'm just trying to stay at steady speed.

Also I had a problem with my transmission already as it wouldent shift to next gear always till I let off gas. Please let me know as much as possible

 

Could be an engine misfire, mud caked in a wheel, or any of a host of other possible causes.

For the shifting issues, I would do a filter/fluid change, and adjust the bands as a start. See if that doesn't help.