I just bought a 94 6.5TD with 153,000 on it. The pump was said to have been rebuilt. I drove it home, approximately 40 miles. Stopped on the way by the auto parts store to pick up some new wipers. I went out started it up started to pull out of the parking lot and it stalled. I restarted it and drove it the two more miles to my house and parked it. I went out later to start it again and would not start. I know that the PMD,s are problematic on these, so I tried a few more times to start it and would not start. I happened to have a spare PMD off of the old pump that the previous owner gave me. I plugged it in and it started right up.
I need to know if I continue to use this PMD can I, reuse the original gasket or do I need a new gasket? Which is better the a thermal paste or the gasket? If you use the paste do you let it get on the two diamond shapes on the back of the PMD or keep it off of them? I was curious because I also want to make my own heat sync and I am going work with what I have for now.

The 'gasket' your referring to is actually a heat transfer pad, and it is reuseable.

Have you already checked fuel filter and supply pressure just to rule that out? Air in the supply can cause lots of problems too. Its so easy to blame the PMD, but I reccommend checking everything else out first rather than jumping to replace the PMD.

What's best is what works best for you. Putting it in the direct airflow and out from under the hood on a heatsink makes it easier to switch next time it fails.

I just bought a 94 6.5TD with 153,000 on it. The pump was said to have been rebuilt. I drove it home, approximately 40 miles. Stopped on the way by the auto parts store to pick up some new wipers. I went out started it up started to pull out of the parking lot and it stalled. I restarted it and drove it the two more miles to my house and parked it. I went out later to start it again and would not start. I know that the PMD,s are problematic on these, so I tried a few more times to start it and would not start. I happened to have a spare PMD off of the old pump that the previous owner gave me. I plugged it in and it started right up.
I need to know if I continue to use this PMD can I, reuse the original gasket or do I need a new gasket? Which is better the a thermal paste or the gasket? If you use the paste do you let it get on the two diamond shapes on the back of the PMD or keep it off of them? I was curious because I also want to make my own heat sync and I am going work with what I have for now.

Pull the diamond shaped plastic covers off the transistors, it lets more heat off of them. Do as you like but out of the engine bay seems to be the way to go, I had mine off IP mounted under the hood and failed multiple times , recovered by retorque of FSD transistor nuts under the plastic covers.

Following one event I filled the cavity with Di-electric grease to try and improve heat xfer per FSD cooler vendors recommendtion, it did not seem to help much. I gave up on trying to make that work and went with Heath unit, I still have the other installed as a back up spare just in case, I'm on a dark road & the Heath tries to strand me, so far so good almost at end of 1st year with it installed.