Headstock clean-up

[Rickabilly]

Diesel engine oil (as opposed to Diesel fuel oil) contains detergent additives specifically designed to remove oil sludge. There is a chance that the sludge was formed by some coolant leaking into the headstock, might be worth making sure no future ingress is possible. You will need to fill with the oil and use for awhile given that the sludge won't hurt anything leave it for a month and use it regularly to get it up to temperature at least a few times, even run with no load just to keep the oil swishing about.
Regards
Rick

[stevec]

Well, although I don't use the lathe on a daily basis I needed the lathe operational, I knew Murphy's Law would get me. So I drained the diesel fuel and filled with ATF. I've been running the lathe and even when not working it I turn it on for a few minutes in forward and reverse. Lathe sounds good and gear shifting seems much better. I think I'll keep it like that and check in a couple of months.
The cover isn't hard to remove but the tools and stuff that gather on top are
At that point I'll see if the ATF seems to be contaminated with the gunk or not, if it is I may change it for fresh. If the shift selectors keep moving as we get into cooler weather I'll know if I've got it licked.

[SnailPowered]

Be careful if the ATF is thinner than the recommended gear oil. I had a motorcycle we pulled out of the dump and it ran with 30 minutes worth of work but the clutch was sticking so we put ATF in it. Well I got so happy riding it around I forgot to consider that the ATF was too thin and I eventually ate the gear box. Wasn't a big deal as "easy come, easy go" but it would have been nice to have that bike. It was an old Yamaha two stroke dual sport bike. I think it was a 200. I remember it was 2-stroke.