I've never had any luck with those solenoid style pumps on a diesel, they just don't last.
Yet again, I will reccomend what I have run for years on my truck, and many other diesel applications, A carter rotary vane pump, P4070 is what I have on my truck, 4-6 psi, self regulating, 72 gph, WET motor, so no shaft seals to go bad. P4594 is the 6-8 psi version. The GP4389 is Diesel/Marine rated, 4-6 psi, but, it's $112 vs $72, and nothing really leads me to believe it's any different than the 4070 other than it comes with less stuff.
The things are bulletproof, and I'm not just saying that because the one on my truck has been good, I'm saying that because that's pretty much the standard fix for every diesel with a dead lift pump around here, I have worked on lots of trucks and equipment with them installed, and they plain old work.