When the car is driving, the foot gently releases the clutch. Where is the problem of jitter?

It shows that the clutch fork, release bearing, pressure plate and friction plate are badly worn, the transfer case is oil-free, the front telescopic sleeve of the rear transmission shaft and its bearing are badly worn black, and the oil seal of the rear cover of the transfer case is burnt. There are only two reasons for this. One is that the shafts of the transmission are not parallel due to the positioning problem between the shafts; The other is that the clearance between shafts is too large. (Wow Kaka, I just graduated with this question)