Look back in the post, I sent a link on how to do a voltage drop test. Otherwise Google it. The correct way to do it is put one lead on the end of the cable and the other lead goes on the opposite end of the same circuit that you are testing. That will give you an accuate reading of how many volts are lost across the circuit. Doing it the way you discribed only shows you system voltage, worthless unless you are checking for a bad battery or cell.
I still say there is a problem, and the new starter is just masking it. No sense in fixing the symptom, go for the problem and never worry about it again.

 

I tried doing it across the cable but it was a pain for me to do last night - will try again. But just for arguement sake - if the voltage across the battery post is 10.86 while cranking, and the voltage across the starter stud and starter body is about 10.76, does not that tell me that I am getting good voltage down to the starter? I would thinking that only 0.1v is getting lost in the circuit. If my cable had a fault, or if the whole circuit was eating up way too much voltage, I would not expect to get close to 10.86V at the starter stud. Will I?
But I will try to get the voltage drop across the cable and/or across the solenoid to kill both of our curiosity !

 

What you are looking for is burned up voltage across the cables as you load them. A battery cable can have next to 0ohms resistance, and still be bad if you use OHMS law. When trying to pass 200amps or more of current through it the slight resistance will kill your cranking voltage. The starter will still appear to work, but the low cranking voltage will kill the starter after a short time.
If you put the + lead on the battery + and the - lead on the starter stud where the cable goes you will measure the resistance of the cable under load.
Disconnect and ground the coil wire and crank the engine. You should get a slight reading on the meter, .1-.4 if it is a decent system. Anything more then .5 and there is excessive resistance. Work your way up the cable connections and you will be able to tell where the bad spot is by the reading you get. Please read this, it will explain it better than I can.http://aa1car.com/library/voltage_drop_testing.htmt
It's the only way to really check out electrical problems. It'll make you tons of $ as a tech since no one ever wants to work on electrical.

 

msbweiland, I am planning to do that tonight. I will post the results. I tend to agree that it is awefully too many starters to get ate up. Although, the last starter I replaced did not really get fried or atleast that's what the tester at autozone indicated.
Denis pointed about a ring gear issue. Is that gear in the starter? The ones I got has 9 tooth. I happened to notice a thread here where someone was having issue with number of tooth in the starter gear. That rose my curiosity a little.

 

After one day of working perfectly, the starter exibited symtom of spining but not engaging again. So, first thing I did was the voltage drop.
I noticed that when I put positive of my multimeter to positive of battery, and negative of multimeter to the side of relay that goes to starter, I read 10 - 11V. It seems the starter cable gets grounded somehow. Is this normal? I checked the starter cable to make sure it is not touching the block anywhere. Anyway, I went ahead and put the negative of the multimeter in the starter stud, with the positive being still on the positive battery terminal. I saw that the voltage reading 0.1V, momentarily shoots up to about 10V when the starter quits spinning, and then going back up to 0.0V.
Next, with a flash light, I was able to see if the starter drive kicks out or not through the flexplate inspection opening. When the exhibiting the symptoms, I noticed that the drive kicked out and spinining but not engaging the flexplate teeth !! So, with a socket, I manually rotated the engine and it engaged !!

 

sounds like the ring gear (the outer part of the flexplate/flywheel) is missing some teeth, so youll be dropping the tranny soon to replace that.

 

Yep - it seems a new flexplate is what I need. I am thinking of pulling the engine and tranny out together. I need to fix some leaks in the tranny anyways. They are not major, but the truck marks it territory and that sucks. I guess I will clean up the engine and dress it up a little as well.