'98 TJ Questions

Hey so I haven't done anything about this yet... It sucks when life gets in the way of fun..

I've noticed as well that there is a shudder when downshifting from 3rd to 2nd but If i blip the throttle between changes it doesn't shudder. Does this narrow the cause down at all? Doesn't shudder any other time other than first gear take off and downshifting 3-2-1 without blipping throttle...

So to keep going with this just trying to work it out. Probably should just take it to a mechanic but I like to work things out and fix things myself....
 
Driveshaft angle? Gears in the rear diff? Bearings in the rear diff? Pull the diff cover and check for metal and how the contact surface is...the down shifting could cause the pinion to move causing the shudder and a hard acceleration same thing with a different movement.