drive line help

[jwhit]

long story short
sbf 347 running t5 5speed with 8.8 rear end
i have noise that i thought was coming from transmission mainly when you were at speed above 40 and pushed in clutch to stop.sounded to me like bearings in tranny were worn almost like mainshaft rattling around
since i was running a used donor trans with unknown miles i decided to tear it down and replace all bearings and worn parts.to my surprise tranny looked good only issue was to much end play on counter shaft
so i went ahead and but in all new bearings and used shims to get end play as close to zero. after installing tranny back in i decided to go for test ride leaving top of tranny tunnel off and i still have the noise
but with tunnel off i can see what maybe issue.it looks like when i push in clutch mainly stopping i see driveshaft and yoke in trans wobbling and thats whats making the noise.if im under load its doesnt seem to be issue
but when you push in clutch i see it happen.since my rear end is 4 link i dont see anyway to change pinion angle but im not sure that is the problem any thoughts would be welcome