Grunting Octavia II

Hi ,

Peculiar problem I have noticed in my car Skoda Laura ( Octavia II as known in India). Been for the 60k service which was due. When i have taken the car from the dealership, noticed a distinct grunting/grinding sound whenever I changed gears.Obviated all the obvious problems, gearbox, clutch working etc, and then noticed that the sound occurs when I let my foot off the accelerator while changing gears.

Finally went back to the dealership and tried to find out the fault. VAS did not indicate any faults.

Finally the cause of the problem was identified as what the dealership termed as "Vacuum Box" , a little black box mounted on a bracket just behind the battery a bit to the left of it with some tubes running out of it.

Seems that this part has to be replaced, since no repairs are possible

Can anyone shed any light on this matter

Thanks