moving down hill?

93f150 4.9l 5spd. i was at my friends house whos house whos driveway is kind of a incline. i throw the truck in 1st gear everytime i park it their cause it is too steep for the parking brake to hold it. i was sitting in the truck fixing something and i thought my friend had walked up and pushed on the truck and it moved, but it wasn't the truck was still in 1st gear and every 10 sec(maybe longer). the truck would move a little. i would say it was slipping in the gears then grabed then stopped then grabed then 10 sec later it did it again. the truck moved 1ft in 5 min. i do have 230lbs of sandbags and salt in the bed. could the weight of the bed and me make it move?

Is it imported sand or domestic? Normal. Try turning the wheel all the way left or right, leave it in gear & setting the parking brake. If that dosen't work, its probibly the ol' "One last straw that broke the camels back" Senario (substitute "straw & camel" with "sand bag & F-150"). So take that last sand bag off (if you can't remember which one it was, guess! You might get lucky and pick the right one!) & set it behind one of your tires so you don't forget it when you leave. Is it still rolling back? This is a good example of what happens to your sense of humor after 14 - 12 hr shifts in a row.

93f150 4.9l 5spd. i was at my friends house whos house whos driveway is kind of a incline. i throw the truck in 1st gear everytime i park it their cause it is too steep for the parking brake to hold it. i was sitting in the truck fixing something and i thought my friend had walked up and pushed on the truck and it moved, but it wasn't the truck was still in 1st gear and every 10 sec(maybe longer). the truck would move a little. i would say it was slipping in the gears then grabed then stopped then grabed then 10 sec later it did it again. the truck moved 1ft in 5 min. i do have 230lbs of sandbags and salt in the bed. could the weight of the bed and me make it move?
Instead of slipping in the gears, I think the compression of the 6 cylinder engine wasn't enough to hold the truck and the engine was turning slightly. I have an '88 F-150 with that same engine and transmission and one day I parked on quite a slope near a convenience store as I was walking away I heard an rr I got back in and tried my parking brake that didn't hold either, needless to say I found a different parking spot.

Compression in the engine is what actually holds the truck back when parked in gear. Compression in the cylinders leaks past the piston rings slowly (it is not a 100% seal) so the holding power of the cylinder or cylinders that is holding the truck at a specific spot leaks off. When it gets low enough the truck moves until it gets to the next holding point (compression built up in another cylinder) which stops the truck until that cylinder leaks compression down and it goes again until the next holding point - and so on.

Dave / Believer45

So the moral of the story is "Unless an opposing force greater than the force being applied (gravity) is introduced as a counteractive, your goin down (hill)! You saving all those sandbags for what.....a rainy day? Did you figure out which sandbag was the last one?

So the moral of the story is "Unless an opposing force greater than the force being applied (gravity) is introduced as a counteractive, your goin down (hill)! You saving all those sandbags for what.....a rainy day? Did you figure out which sandbag was the last one? i just have the sand bags in their so i can get traction casue we had like 6 snow storms already and my tires are junk

i just have the sand bags in their so i can get traction casue we had like 6 snow storms already and my tires are junkaghhhhh!!!........sorry,just slipped out.