The other day when adding power mirrors to my 740 I found why the drivers side window was a bit jerky in its operation, there was one of the tuning fork shaped guides in the bottom of the door. It was all hard but I forced it in place, then went to the Volvo dealer to get a new one. The dealer had no idea what it was and told me they couldn't get it anyways as it was an old car- the same dealer that tried to sell me a flame trap complete with housing and hoses for $85.00 cdn It took a while to get just the insert. My question is what are these things called and where can I get them ?? I think I should replace all three per side