I have a 300mm VRI lens that has some stiction and squeaking when turning the MF ring, even when the A/M focus switch is set to M. The issues goes away after turning it back and forth for about 45 seconds. I'm thinking it happens either because it's just cold or because the previous owner didn't use the MF ring very much. There is no noise when auto focusing. Is this normal for this lens? After using the lens last night (when the sound went away after 45 seconds), the sound returned again this morning but much softer and went away after only 10 seconds this time. I'm thinking it's just a transitory thing from lack of use, like maybe the factory lubrication needed to be spread around a bit but I'd like the opinions of others to be sure.
I think you will find the lube inside the mechanism has dried up, needs to be stripped down, cleaned and re lubricated, had it happen on one of my 200- 400's, wasn't cheap either about $400 from memory