Hey guys,
been trying to diagnose a harsh “clunk” noise in my GC8 wrx when transitioning on and off the throttle that’s progressively been getting worse and worse. now it’s at the point where the whole car jolts when changing gears or even when letting off light throttle. There’s no real abnormal noises otherwise, only other issues i’ve had with this transmission is half a tooth falling out with the oil the first time i changed it 20,000km ago.

I finally had a chance yesterday to get underneath and start checking all the usual causes like drive shaft center bearing, U joints, diff carrier bushings etc. but they all seemed in reasonable shape.
however when i tried turning the driveshaft in gear, its got about 1/6th of a turn free play before it tries to turn the front CV axels, which visibly wobble up and down slightly when they begin to turn. i know its got an additional gearset and center differential for slop to occur compared to the rear, but that amount of movement still seems pretty excessive to me?

any help is appreciated, TIA