Got another project,need some advice
 

I just got myself another spring project,82 300TD,solid car,however,not driven much lately,so,here are some issues that I need some advice before I start working on it:
Car started in 10F without the glow plug light showing on the dash,needed a crank for 20 sec.,however,I assume that if none of the plugs are working would not start in this weather...I can hear the relay clicking on,however after waiting 2-3 minutes,I dont hear the disconnect click?,how about that.
Car has a nasty metallic clunk before it comes to a complete stop and trannie downshifts,it comes from driveshaft/rear end,only when it downshifts before it stops,it shifts quietly up ?,seems like there is something loose where the driveshaft is connected to the rear end.
Any input will be helpful.

If you go to dieselgiant.com, there is an excellent article on troubleshooting the glow plug system.

The clunk when stopping is due to insufficient vacuum reaching the transmission modulator. In other words, you have a vacuum leak somewhere. On my car, the clunk problem was due to intermittent leaks in the vacuum switches mounted on the valve cover. I ended up just bypassing them to correct the problem.