i have a v70 awd 2.5 turbo ,i recently had a new transfer box and gearbox fitted. when the prop shaft from the transfer box is fitted to the viscose connection before the back axel it makes a wining sound and the viscose connection gets hot and so does the transfer box. when i disconnect the prop shaft from between the transfer box and the viscose connection and drive the car as if it is just front wheel drive,, the viscose connection stays cold so does the transfer box, but the wining appears again at about 15;20 mph and disapears when you stop.is there any thing else it can be other than the viscose connection, what does the viscose connection exactly do???? please help.

 

The Viscous connection is like a clutch setup in the driveshaft. When you hit about 30MPH then is unlocks the driveshaft and you only have front wheel drive.