The '77 F150, 2wd, Auto-302 cid, was making that familiar clicking, at times, when just taking off from a stop.
So replaced u-joints and IT STILL HAPPENS, altho not all the time at every stop.
What's next?
The yoke at the front of the driveshaft?

 

Sounds like the differential itself.

 

Not uncommon, remove driveshaft and grease the splines in the yoke going into the tranny. We even used to install a weak coil spring into yoke to help with the sticking.

Somewhere about your vintage Ford started using the Teflon coating on the splines, that helped a lot. Just to make sure you are not chasing ghosts, check all bolts securing rear end to leaf springs and springs to chassis.

 

This sound is coming from the front half of truck and it's 2wd. Hope to rule this out.

Time will tell

Thanx

 

Makes sense

I'll grease her up this weekend

 

Oh oops

 

Thanks to you both!