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Well, I haven't even had the chance to do the "Look at my new truck!" post before I ask for some help/info. Battery light came on a few days ago on the way to work. On the way home I stopped by Advanced Auto Parts and had a system check. Both batteries came back "Good". Then the guys did a system test and came back with a "Charging System Problem". Theres a pic of the receipt below. So pretty certain I need a new Alt.
I know a lot of guys like to get their stock alternators rebuilt by an "electric servicer" or "auto electric shop". But who is this? That's not Auto Zone, Napa, Advenced etc... correct? What kind of search do you do to find one? (I am in Madison, WI) Then pardon my ignorance, but how do I know if my current Alt is stock? (I just bought the truck 2002 with 124k mi) Pic from the top below
The next question would be, which Alt should I buy? I don't do anything that requires more than the stock output. My FTE searches came up with
-Ford part number F81Z10V346EBRM (Motorcraft number GLV8666RM).
-"Just go to Napa and get one"
-and then a 185 amp DC Power unit from FICM (I wouldnt have a problem spending the $$ but I need the truck this weekend)
- Alt from OReillys
Initially, I wasn't sure if I had the 2 Alt set up or not, so I went home popped the hood and started looking. Almost sure I do not. When and what model trucks was the 2 Alt setup used?
If you have dual alternators, the second alternator isn't very visible from looking under the hood, especially if you've never seen it before.
It is best to look from under the truck, by the passenger front tire. The second alternator (if equipped) is in the lowest position on the front accessory drive system, closest to the passenger frame rail.
There is no particular year that the dual alternator system began being offered. It was available on all years of the 1999-2003 7.3L F-Series Super Duty. It was simply an option, both a la carte and with the Ambulance prep package. But you didn't have to order Ambulance prep to get dual alternators. You could order it separately.
On the whole, however, the option is somewhat rare. By and large, most pickups were not equipped with dual alternators, because it was an extra cost option that dealers didn't check the box for, presumably to keep the MSRP from ballooning for features customers can't see or touch. A customer can easily feel and smell the leather of Lariat, but one can't easily see the second alternator under the hood.
Judging by the photo of your alternator up top, that looks like an original OEM small case 6G. This is not to say that the alternator couldn't have already been rebuilt, however, the pink coating on the stator windings indicates that the stator is OEM, not the cheaper Chinese replacement stator.
All alternators from Ford and Motorcraft for this application are rebuilt/remanufactured. That is what the RM means at the end of the part number. Neither Ford nor Motorcraft sell new units for our old trucks.
Ford and Motorcraft have revised the part number to this alternator several times. At least one of these revisions may have involved a change in diode specification (improvement) and regulator specification (improvement). This should not be taken as gospel, because by the time I arrived this deep in research on the 6G alternator revision history, I had come to the conclusion that I didn't want to bother with 6G alternators of any type, large case or small case, as there are newer more efficiently designed alternators available that were not in production at the time the 7.3L was.
If I have or don't have dual alternators, is the main alternator the same? Looking at a few vendors and see phrases like "Upper" or "Single". Heres a screen cap from RockAuto
So it seems like you opt for a non over the counter (Autozone, Oreillys etc) alternator? I might have to go that route to get her going for the weekend, but it would be good to know
My Alt. has a sticker on the top that says "REBUILT", so I would guess that if that sticker is not there, then it is stock.
As the other guys have said, 2nd Alt. is on the passenger side, you can look at the sticker in the engine bay that has the belt diagram. That will tell you where the 2nd Alt. is located.
Though I would think if you've got 2 alternators you shouldn't have a charge issue.
Did you double check all your connections? Battery terminals, the positive lead is tight for the Alt.?
If you're looking for an upgrade that's ready to go this weekend, go with the 6.0 alternator, new not rebuilt. Otherwise I'd recommend a new, not rebuilt 7.3 replacement from your favorite chain store.
If you have dual alternators, the second alternator isn't very visible from looking under the hood, especially if you've never seen it before.
It is best to look from under the truck, by the passenger front tire. The second alternator (if equipped) is in the lowest position on the front accessory drive system, closest to the passenger frame rail.
There is no particular year that the dual alternator system began being offered. It was available on all years of the 1999-2003 7.3L F-Series Super Duty. It was simply an option, both a la carte and with the Ambulance prep package. But you didn't have to order Ambulance prep to get dual alternators. You could order it separately.
On the whole, however, the option is somewhat rare. By and large, most pickups were not equipped with dual alternators, because it was an extra cost option that dealers didn't check the box for, presumably to keep the MSRP from ballooning for features customers can't see or touch. A customer can easily feel and smell the leather of Lariat, but one can't easily see the second alternator under the hood.
Stand in front of your truck (on the passenger's side) with the hood up and look down underneath your A/C compressor. If it's an open area then you have the single alternator. If you see something taking up space with a pulley (with a belt around it) and it looks like the alternator up top then you have the dual alternator setup. You will also have an extra idler pulley to help the longer belt route around it. You will also have a sticker in your door frame (I have a crew cab so it's on the pillar between the doors on the driver's side) that says that the truck is not an ambulance prep package.
The lower alternator is the same alternator but 'clocked' differently. It has the same mounting brackets but the back is turned to line up differently with the case. Some lower alternators were the 4G case and some were 6G. The 4G case has a black back on it where the 6G does not.
After some quotes for a rebuild I decided to have new ones built. Since I have two of them high amperage was not a concern. Here's what I went through:
If you do have the dual alternators like I do (and you plan to do it yourself), set aside some time. I did the upper alternator in about 20 minutes (I got the large case 6G so I had to do some grinding on the bracket). The lower one was a different issue. The only way to get at the bolts (and get the alternator and bracket in or out) is to remove the fender liner. I didn't do it all at once but all said and done it took me several hours overall to do the lower one (not including the time that it took to figure out how to unbolt the lower bracket...that was another couple of hours in itself).
So far the new alternators are running like champs. Colder days my voltage is 14.3-14.4VDC and on warmer days I'm still seeing 13.9VDC at idle.
I picked up a new gold standard from Autozone. I read reviews about the bearings going out on them. So I bought one and a month plus one day later the bearing started to fail. You could hear a loud growl coming from under the hood. When you looked at the pully on the motor it was wobbling. Autozone said that since it was still charging that I would have to wait for it to completely fail (maybe the pulley fall off?) before they could warranty it.
So I went down the street and bought a Wilson before I started my roughly 1000 mile trip. I didnt want to get stranded 100 miles from no where.
The Wilson failed around a year later. I took the Wilson to a local rebuilder and he took it apart and showed me the cheap Chinese parts and shoddy workmanship.
I ended up buying a new NAPA.
Make sure that the pigtail is on tight or the check battery light will come on, then go off and then come back on again.
If the 6.0 fits, I would have liked to have known that before I put this one on...
Some lower alternators were the 4G case and some were 6G. The 4G case has a black back on it where the 6G does not.
No 1999-2003 F-Series Super Duty F-250/350/450/550 came with a 4G alternator in the lower position as original equipment from the factory. I think Alternatorman is in error, as he posted that info on his website.
Hey Chris,
With your write up and thread I am going to go with the 6.0 alternator. That way I get a little more out of it. Question...From other responses in your thread, it seems like I CAN keep the 6.0 pulley on it and I don't HAVE to clock it. Is this right? Also, I didn't see anything about needing different connectors. My 7.3 connector will work just fine with the new 6.0 Alternator?
I have 10lbs of crap to haul in a 2lb bag this weekend. Time is at a premium.
BBD,
Thanks for the input. I might have to change my "favorite" chain parts store. We have Advanced, OReillys and Autozone all in a 5 mi radius, NAPA is a bit further but sounds like it may be worth going out of the way for
Brian and P4IN COMM4NDO,
Thanks for the info. I did look on my door panel and found the "Not an Ambulance Package sticker". Also checked the belt diagram and it clearly doesnt route to a second alternator. Checked connector and it seemed to be tight
10-26-2016, 02:11 PM
