1996 Ford F-150 clutch problem

After you have located the clutch slave cylinder, have someone depress the clutch pedal. You should see the piston of the slave cylinder extend somewhat. If it does not, either the slave cylinder is bad, or the master cylinder. Ensure that the master cylinder resevoir has the recommended amount of brake fluid before doing the more complicated work.

If you change the master cylinder it is always a good idea to change the slave as well. The pressure from the new system will be harsh on the used slave cylinder.

Correct, on the bell housing.

Yes, it is quiet a job. You may be better off having your local dealer test to see which one is bad, if it is either. I have included some instructions to remove the slave cylinder. This should help you locate it more precisely if you do decide to check it. I would advise letting a professional check out your vehicle if you feel uncertain about your abilities as working on a vehicle can be dangerous, especially without a lot of experience.

Removal of slave cylinder:

Disconnect the negative battery cable.
Disconnect the fluid coupling at the transmission, using the clutch coupling removal tool T88T-70522-A or equivalent. Slide the white plastic sleeve toward the slave cylinder while applying a slight tug on the tube.
If the special coupling tool is not available, the fluid coupling can be uncoupled by using a flat-bladed tool. Carefully pressing in around the coupling while applying a slight tug on the tube.
Remove the transmission assembly.
Remove the slave cylinder-to-transmission retaining bolts.
Remove the slave cylinder from the transmission input shaft.

Let me know if I can help in any other way.

To have the clutch system replaced, I would say anywhere from $800 - $1,500 dollars, depending on location and what garage you choose. I am not sure what they would charge to look at your clutch system though. If you are certain it is one of the cylinders, you are better off changing the clutch system though.