Posts to build up posts...
I have a vibration in my 98 T100 4x4 manual shift 3.4 liter. I was told by previous owner it was throwout bearing...I can't believe it. It only happens under acceleration with clutch engaged.
Driveshaft u joints and center support bearing are all new. Drive shaft recently balanced.
Toyota tech told me input shaft bearing to transfer case has a noisy/worn bearing. I can hear kind of a gritty bearing at 40 mph or so, but not too bad. Considering swapping out my VF1A tranfer case to see if it goes away. Doesn't happen with rear drive shaft removed when in 4WD, so could also be a rearend problem?