Universal joints allow travel shafts to move along with the suspension while the shaft is normally moving so power can be transmitted when the travel shaft isn’t in a right line between your transmission and travel wheels.
Rear-wheel-drive vehicles include universal joints (or U-joints) at both ends of the travel shaft. U-joints connect to yokes that also allow drive shafts to move fore and aft as cars go over bumps or dips in the street, which successfully shortens or lengthens the shaft.
Front-drive vehicles also apply two joints, called continuous velocity (or CV) joints, nevertheless they are a several kind that also compensate for steering alterations.
On rear-drive vehicles, one indication of a donned U-join is a “clank” sound when a drive gear is engaged. On front-drive vehicles, CV joints sometimes make a clicking noise when they’re donned. CV joints are included in protective rubber shoes or boots, and if the footwear crack or are usually destroyed, the CV joints will eventually lose their lubrication and become damaged by dirt and wetness.
A U-joint is found in both front wheel travel and rear wheel travel cars. Although they are different in design, they have the same reason for giving the drive teach some flexibility. This is necessary as all cars and trucks flex while in movement.
U-joints are located on each of the ends of the trunk travel shaft, whereas CV-joints are found on front wheel travel autos. Each allows the travel shaft to rotate as the differential techniques in relation to the others of drive train mounted on the chassis.
The U-joint functions to save wear and tear on your vehicle’s transmission. Inability to have a universal joint alternative done when needed can lead to substantial destruction to your U Joint china vehicle in the future.
There are a few indicators 
that U-joint or CV-joint is failing. They incorporate: