I had my 300 f4 out this weekend doing some birding and it started making a noise when trying to focus. it sounds like a clutch slipping, when it is making the noise it doesn't focus. if I let off the shutter button and then try it again and it works. Tryed it on a second body and it does the same thing. So my questions are 1. is the auto focus dying? 2. is it possible to get parts for a lens of this age? 3 if so where would be the best place to send it in the US? 4 any idea of estimate of repair cost, I can get a new lens for $500-$600, so a $400 repair bill makes it a little iffy, I for that I could save and get a new af-s version.
Well, you never know till you send it in, but since the IF-ED version doesn't have a motor hopefully it's something relatively simple/cheap like the gears need cleaning or something got knocked out of alignment. Whether parts are still available is a good question. You might try calling some Nikon authorized repair services and asking. (I wouldn't bother calling Nikon USA; they don't know and they'll probably give you bad information. A few months ago when I called them about an old lens they told me sure! Send it in, they had the parts for it! A week later the lens was returned to me, untouched, with a note saying parts aren't available.)
Sure sounds like something is broken or loose in the lens.
Whether parts are available, I don't know. With a lens that old, chances are good that a repair center won't know, either, until they open the lens up and find out what's wrong. It may be that some parts are still available and some are not. It may be that it doesn't even need parts. Do you feel lucky?
If there is an authorized repair center near you that will give you a quote, I'd give them a try. Otherwise, I'd send it to Nikon. They'll give you a quote, and if it's too much you're only out the cost of shipping.
I would be surprised if the repair at Nikon were less than $250, and it could be more. But that's only a guess.
If it's the 300/4 AF screwdriver model produced from 1987 to 2000, mine started making a noise as if the drive shaft had a dry bearing. I took it apart and lubed the screwdriver shaft, which was fairly simple to do and seemed almost to fix it, though it still made the noise intermittently. Sometime later the MF ring dropped a screw and locked up, so I decided to send it in to Nikon. I told them about the previous noise as well as the new problem.
I got a quote for a bit under $200 flat fee for a complete repair and C&A (to clean, check for, and fix both problems), and sent it to Nikon (NY, I think). Got it back promptly, and I don't regret doing this at all, although it's made the lens a keeper, and meanwhile I also have the 300/4 AFS!)
So, I highly recommend Nikon repair dept, not a third-party repair shop. BTW it's a fantastic lens (in some ways I even prefer it to the AFS), and well worth getting fixed properly. Good luck!