I have a 98 ranger that I just put in a new clutch, slave & flywheel. I got everything back together & bleed the clutch. I didn't fill the tranny with fluid because I didn't to drain it again if I had to take everything apart. Anyways I raised the rear up then when I started it I went to go put it in 1st when the tires started moving. Any suggestions? Just want to clarify I didn't have it in 1st it was just before I shifted into 1st.

 

Your post is a little confusing but it appears that your clutch is not disengaging.

If you take the truck out of gear, engine off, rear wheels off the ground, can you rotate the drive shaft by hand?

Now in gear, engine off assistant stepping on the clutch, wheels off the ground, can you turn the drive shaft?

It could be that the input shaft is just being carried a bit by the pilot bearing, but it could be that your clutch is not fully releasing. Knowing which is happening will tell you what to do next.