I have a '70 F-100, 302/C4 that has developed a new noise. I noticed it yesterday after driving to Kirkland and back, there is a repetitious 'click' when I am stopped with the transmission in reverse. I have not been able to dig in and test it much yet, I will update this once I have been able to. I did not see if it is at speed or just when stopped, heard it after backing into the driveway and decided to let her sit there until I could diagnose.

For now, I wanted to see if anyone has encountered a similar issue and had any ideas as to the issue. Transmission is about 2 years old (I would estimate under 5k miles) and the third member is freshly re-done with a new posi. U-joints is about the only thing I can think of which would be directional, anything else I could think of (torque converter, flex plate, engine noise) would be present regardless of the gear I am in (or at least in my mind I rationalize they would be).

 

I'm thinking you nailed it on the U-joints. Look at them and see if they have a zerk fitting. If so give 'em some grease and test drive. Me personally, I'd go straight to pulling the driveshaft so you can see by hand if they are tight or move freely.

 

I started the truck the other day with the intention of disconnecting the driveshaft to confirm it was a u-joint noise and now I am more confused because the noise is gone and I did nothing to even try to diagnose it yet, let alone trying to fix it. I am still going to check/grease my u-joints for S & G but apparently this problem has fixed itself...for now.