Long story short: Replaced a bad U-joint in the rear driveshaft (propshaft?) in my D1, and was horrified to see just how bad it was. Broken end cap and metal within was worn down about 2/3. (Attempted to post a pic, but was rejected. Not enough posts? Anyway...)

My question is: what, if any, long term damage has been done to the rest of the drivetrain? The remaining 3 U-joints appear to be in good shape, but I'll soon be replacing them as well in the interest of "ounce of prevention," etc.

Thanks, awesome forum!

 

Most likely very little. You can operate with one shaft removed, if placed in locking mode. While you work on the other. You'll be changing out fluids in diffs and transfer case and can check for metal fuzz with a magnet.

 

Already replaced the bad U-joint, also changed the gear oil. (Slowly working my way through Disco Mike's hi-mileage overhaul list.) Didn't see more than a light dusting of metal particles stuck to the plugs, so I remain hopefully optimistic. Thank you sir!