I have a 1981 Vauxhall Chevette & am currently re-furbing the gearbox. The main shaft has a worm gear (which drives the speedo) in front of the bearing I wish to replace. I am beginning to think it was put on hot then shrunk into place & applying heat with my blow torch does not help. I am thinking of hiring a pipe freezing machine to freeze the shaft then use my blow torch & see if I can get it off that way but wondered if that might damage the structure of the shaft. Has anyone any knowledge of doing this sort of thing. Thanks.