This seems to be more of a first gen d max thing so I will post it here. We had an 04 come in at work with an intermittent no crank sounded liking it was grinding the flywheel noise. Found nothing physically wrong, starter and flywheel were in good shape. Finally after a call to tech assist we learned that between the battery that supplies power to the under hood fuse block and the starter solenoid, it was dropping 1 volt across the entire circuit. From the battery to the fuse block it dropped half a volt and from the starter relay at the fuse block to the starter solenoid it dropped another half a volt. GMs fix is to replace the under hood fuse block which runs in the neighborhood of 400+ dollars but it did fix the problem.
My dads truck has had this problem since he got it last fall. We've tried countless starters and even a fly wheel with no real luck. The current starter acts up maybe 4-5 times a month. I am going to try a Ford (i know the F word) starter relay and see if it helps anything. Basically the original starter relay in the under hood fuse block will stay put and just turn the ford starter relay on which will be mounted close to the starter, probably on the firewall. A heavy gauge wire will run from the battery to the ford starter relay, and then when its switched on another heavy gauge wire will go to the small wire at the starter solenoid. This should provide a solid 12 volts everytime and eliminate the voltage drop. Its worth a shot if you are at wits end.
My dads truck has had this problem since he got it last fall. We've tried countless starters and even a fly wheel with no real luck. The current starter acts up maybe 4-5 times a month. I am going to try a Ford (i know the F word) starter relay and see if it helps anything. Basically the original starter relay in the under hood fuse block will stay put and just turn the ford starter relay on which will be mounted close to the starter, probably on the firewall. A heavy gauge wire will run from the battery to the ford starter relay, and then when its switched on another heavy gauge wire will go to the small wire at the starter solenoid. This should provide a solid 12 volts everytime and eliminate the voltage drop. Its worth a shot if you are at wits end.