ive checked the frame and there are no cracks. If i lurch the truck forward hard or rock back and forth (mostly the rocking) the truck creaks. It happens randomly. Has anyone come across this?

 

Check your body mounts.

 

i looked at them and i didnt see anything wrong with them. Nice and solid. Are they a pain to replace? The truck bed moves a little but it doesnt make any noise when i move it.

 

The frames on these truck tend to twist a little on uneven terrain. Nothing really to worry about. It is better to have a little twisting action than to have a really rigid frame.

The cab on my truck even flexes a little on uneven terrain. You can hear the door move in the opening as you flex the frame.

 

yah im not too worried about the frame flexing. The one thing i dont like is the creaking. It can get annoying pretty quick.

 

Might be shocks/suspension creaking.
Come to think, my 86 F-150 creaks a bit when cold. Mainly when the temps get down below 20 degrees. Creaks disappear after driving for a while unless it is really cold.
Heck, really makes some noise when water has managed to freezed in the suspension on snowy/wet/cold days.

 

There was a post awhile back on creeks and pops of the frame. The post showed the tranny crossmember is relieving stress. On a flat surface loosen the tranny mount bolts, then loosen ALL the crossmember bolts, (top and bottom rail channels). tighten all the crossmember bolts, THEN the tranny mounts. ........Mine stopped "creeking"
Reamer
'86 stepside 4x4

 

my truck does the same exact thing. the sound is comming from my rear shackles. i guess the bolts have to be lubed

 

My truck would always do this after it rained. I narrowed it down to the Leaf spring bolts. So I ended up removing and lubing the leaf spring bolts. This took care of it. Now I have to change the rr sway bar end link bushing as they are rubbing on the frame and making a new creeking sound. I got the Energy Suspension bushing for this job. Country