Hey all TD experts out there - I have an 82 300 TD and when I lock car using central lock, hatch is last to go and is a loud "clunk". Fearing corrosion causing problems in the linkage, I removed rear panel and looked at everything. Seemed okay - well greased, just required decent effort to make lock and unlock. Just in case, sprayed with white grease. Maybe the system is meant to lock that way. Any pointers?