My 1998 12V has been intermittently cranking slow for about 6 months. Recently it started happening more often and more severely. It would crank slow and then sometimes stop turning at all but with the starter still trying. I assumed it was the batteries so the first time I couldn't get it to start at all (about a week ago) I bought 2 brand new Exides. No change. I can still get it to start after a few tries and once it starts it runs great. No smoke, no noise, good power. I checked the resistance of the battery cables and they were fine so I pulled the starter. It had never been out before and with 220k and a lot of short trips I figured it was toast and took it to be rebuilt by a very good local shop. They reported that the contacts were rough and the armature was shorted and did a full rebuild. I put it back in tonight and... no change. By watching the fan when cranking it seems to go normal speed until it gets to a certain point and then the engine just stops and the starter strains against it. Again once it does start it runs great. With a socket on the alternator I can turn the engine but it is pretty stiff in some spots. I checked the coolant and oil and they aren't mixed so I don't think a leaking head gasket is allowing water into a cylinder and hydro-locking it. I also took the belt off in case the AC compressor, alternator, or something is causing an issue. No change without the belt. That's as far as my diagnostic brain can go tonight. Any ideas here? Could the PS pump, vacuum pump. or injection pump cause this?

Did they put in a new solinoid plunger on the rebuild? I'd bet they did. I think your problem is still with the starter and/or connections to it somehow. Could it be from what you test as good cables but with a lot of battery draw the starter slows down from a weak spot in the cables. Test your battery voltage before and after an attempted start. If the batteries are drawing down very fast there is a short inside the starter.I think it's still the starter to be honest, but, don't go pulling it on my account anyway, till you check every thing connected first.

You can also check your cables...use a multimeter on vdc from one end of the cable to another...you shouldn't have any...

Slow cranking is most likely starter brushes are wiped out.

http://www.fostertruck.com/dodge/

Brushes should all have been replaced when the starter was rebuilt. I checked voltage drop both + and - from the battery to the starter today while cranking. There was less than a half volt on each which surprised me. Then miraculously while checking the ground side "one last time" it started cranking really fast. I shut it down and restarted it a half dozen times and it cranked perfectly every time. So now I "fixed" it but without doing anything... great. I'll see if I can get it to show the bad symptoms again tomorrow. Any ideas?It looks like my + cables could use replacing so I'm looking for a source of some 2/0 cable and terminals where they wont cost me a mint. I'd like to make new cables for another car and a couple sets of HD jumper cables too while I'm at it. Anyone have a favorite source for welding cable?

You're on the right track with welding cable in 2/0...its what I used as well.Try a farm and ranch store...never know what you'll turn up there.

Flaky grounds do weird things........

So if its not the starter then I would follow the cable route. Make sure if you have them made that all the proper wires are soldered into the terminals for you.

Problem is solved. I took the truck to the shop that rebuilt the starter. Apparently there is a clutch in the starter and mine was slipping very badly. It was supposed to be replaced with the rebuild but the tech there took out the old one, set it next to the new one, then mixed them up and put the old one back in again.