As to draining the oil:
On the FP4NC there are two gearbox reservoirs...The rear one is where most of the shifting takes place...The two are made so that the rear, feeds the front by spilling over
a cast in divider.
Pretty sure you can drain the rear sump without messing with the front...but just in case here are the details for both:
Rear sump is drained via a hex key plug in the bottom face of the "Y" slide between the dovetails....Got to remove or pull back the "Y" bellows in order to see it.
That is pretty straight forward and easy....
The front sump is another thing.....Here is the drill, or at least how i do this..
Guessing your machine has hand wheels. Move the "Y" slide forward till it hits the limit switch using power. Select hand feed , pull the hand wheel out and continue feeding forward
using the hand wheel, past the normal limit stop....you will reach the safety stop and the machine will immediately go to an E-stop condition and shut down....
Now if you look under the "Y" slide and just in front of the wiper on the vertical face of the "Z" column you will see another hex key plug, and it should be just clear of the wiper.....
Before you remove the plug, fabricate a drain trough....I made a simple one out of some scrap sheet aluminum.
Visualize a flat piece with the sides bent up at almost 90 degrees...the folded width of the piece fits between the box ways...there is a short section at one end where the bottom continues
for maybe an inch of less where there are no sides...sort of a tongue if you will....
Using duct tape i stick the tongue to the flat face of the "Z" ways between the boxes on each side....I place the tape up close to the top of the slide, i bend the tongue a bit so that mu little piece of sheet
hangs out and down like a shed roof.....
When you pull the plug the oil will run down the face of the "Z" ways and be deflected by the sheet metal out form the column enough so that it can be directed into an drain pan that you placed on top of the "X" axis....
Be sure to de-grease the face of the slide before applying the duct tape.....
One the oil is out and the plug replaced, you need to get the slide back into its normal operating range...With control power on (CRT lit) wind the hand wheel back to get the slide off the far limit switch and allow
clearing of your E-stop condition....
Cheers Ross