77 chevy scottsdale 10 side step 350 driveing the other day and I heard a pop! and I was free wheeling, I thought the clutch went out so I coasted home. parked it. it has been feeling funny two days prier kind of a rummble or vibration when I press the pedal only in the enitial pressing of the pedal,half way in it stops. tried it later, the pedal still works but doesnt want to go any where. engine revs but no go go please help 
I gather that this is a manual transmission truck. With the engine running, the clutch engaged (pedal up), and the brakes ‘on’, what happens when you shift into First, into Reverse, and into High? Is there any noise coming from the transmission?
With the front wheels heavily blocked and one rear wheel off the ground, turn the rear wheel and see what is turning and what is not. Is the drive shaft turning? If you hold the drive shaft from rotating, does the loose wheel still turn? If the drive shaft will turn, put the transmission in high gear and try to visualize the transmission input shaft. You might be able to see the transmission input shaft by taking the bottom cover off the bell housing.
Get back to us with what you find.
yes its a stick, she starts up, goes into all gears fine but when I start to go forward its almost like the emergency break is on. I havent been able to lift the rear off the ground. no level place on my block I have access to at the moment.
no noise when shifted into gears
So with the clutch engaged (pedal up) and transmission in gear, the engine just revs freely?
If there is no whirring, grinding, or gear noise from the tranny, the power transmission break is probably in the clutch or input shaft of the transmission. If there is transmission noises and the drive shaft is turning something is wrong in the rear end i.e. broken spider gears, broken axle, etc.
Let us know what you finally find out.
no, guess I should ellaberate, after sitting for while after the episode. the clutch pedal will engage and allow free movement from gear to gear. but has rummbling or vibration when you push the pedal at the begining stage. first couple of inches as you press the pedal down. upon trying to drive the engine revs up but she is realy fighting to go like the brake is on. she tries but but it is a real effert to move. so being a little weary of not wanting to damage anything else I stopped.