My '89 4WD 2.9L 6CYL is making a clicking noise once in motion. Replaced the flywheel, clutch, and transmission but continue to hear what sounds like a playing card running against the tire of a bike, works the same way too, upon getting into gear and moving it will slowly begin to click and progressively gets faster and louder as the truck begins rolling faster. It sounds and feels as though its right underneath your feet. Shifts extremely smooth and has no other issues, the 4WD is disengaged. Doesn't seem to happen in reverse, although I haven't gotten it moving very fast in reverse. Thanks ahead for any info/help.

 

Welcome to the forum

If you still use Auto hubs up front then that's the clicking, one is not fully disengaged
Could even be a manual hub issue

 

If you're referring to the 4WD locking hubs mine I believe are manual, you have to twist them to "lock" or "free" I was considering it may be these or the wheel bearing/hub assembly, thank you for the quick response

 

Jack up front wheels and spin each one

Speedometer still working OK, broke strands in cable can cause clicking but needle would also jump

 

Could be U-Joints !