I have a 1998 Chevy S10, 4.3L with a manual transmission. I tried to put the truck in first gear but it would not engage. I noticed that the clutch seemed like it did not have any pressure on it when I tried to depress it. I checked the master cylinder and it was full of fluid. I looked underneath and could not find any loose hoses or anything with evidence of leaking. I turned the truck off and was able to put it in first gear. With the help of the slope I was on, I was able to get the truck started in first gear and make it back home. Now what? I don't know where to begin. Any help would be greatly appreciated.

The hydraulic slave unit may be shot or you have air in the system. If it's the latter, the system only needs bleeding. Many of these situations come from not changing the brake fluid in the system every 2 years. The lubricity of the fluid needs replacing and soft part debris and corrosion needs purging. Overfilling the clutch master cylinder reservoir can also lead to premature death.

Hydraulic clutch system capacities are small and are very unforgiving of any air in them. Proper technique is a must or the pedal will continue to go to the floor, as many shade tree mechanics have found out the hard way. I use the fool-proof Brake Bleeder Economy One-Man, Cal-Van Tools, No. 247, brake bleeder. It cost me $2.99 and has a one-way check valve built into it. Regular preventive maintenance is the cheapest way to keep any brand of car or truck going several hundred thousand miles.

I have a 1998 Chevy S10, 4.3L with a manual transmission. I tried to put the truck in first gear but it would not engage. I noticed that the clutch seemed like it did not have any pressure on it when I tried to depress it. I checked the master cylinder and it was full of fluid. I looked underneath and could not find any loose hoses or anything with evidence of leaking. I turned the truck off and was able to put it in first gear. With the help of the slope I was on, I was able to get the truck started in first gear and make it back home. Now what? I don't know where to begin. Any help would be greatly appreciated.
I have tried locating the slave cylinder to inspect it. However I could not find it in the usual place. From what I have read, I must drop the transmission in order to replace it. Is this true or is there an easier way to reach it?

Also, I have never changed the fluid in the system. Obviously, this will be the first thing (easiest thing) I try and hope that is all that it is. Thanks for your help.

Follow the clutch hydraulic lines.

The throwout bearing busting can also cause that kind of sensation.