Ok, first off I bought this truck about 1.5 months ago and before I bought it, it had two brand new batteries and a brand new alternator installed. To be honest when I test drove it I don't believe the TC ever locked up(didn't know what TC lockup was when I bought it.) The transmission fluid was real brown and smelt really burnt, so I dropped the pan and changed the fluid and filter and adjusted bands(about 6 qts is all i got changed out. I didn't do I complete flush.) So now when the truck is cold, the TC will lock up at about 45-55mph, and the transmission starts to shudder until I get up to speed. After I get on the hwy it will stay locked in for about 4-5 miles then it starts to unlock and lock a couple of times till it finally stays unlocked and wont relock the rest of the drive into work. So I think I am starting to have the a/c noise issues. I first checked the codes and I get no codes. When I got home I checked the DC voltage at the battery and get 14.3 or so. I then switched my meter to ACVs and it reads 30.8???? I believe I have the meter set right for AC but not sure. I included a picture with the setting to make sure its right. I then remove the alternator fuse and check again on ACVs and it drops down to 26.3?? Are these readings right? When I check the ACVs at the fuse I get nothing, I just get the readings at the battery??

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I'm not sure if my volt meter is on a low enough setting for the ACVs. I also don't know if the fluid change had something to do with it? Fluid is burnt and brown in color. Then I replace 6 qts of new fluid and it starts this? Maybe it needs a complete flush?

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Im not sure if this had anything to do with my bad gas mileage also. I got 12.5 mpg when I bought the truck completely stock. Then I added 4" straight pipe and a BHAF and I have ran two tanks and it only brought it up to 13mpg.

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Alrighty, I removed the alt fuse again and took for a test drive. And still the same, not locking up on the hwy. Also, when I removed the alt fuse, my airdog 150 ran all the time??

Failed diodes. I've seen them fail out of the box. Most re-builders or manufactures tend to cut corners and use cheaper China/Japan diodes instead of quality American so the AC voltage is higher.

Failed diodes. I've seen them fail out of the box. Most re-builders or manufactures tend to cut corners and use cheaper China/Japan diodes instead of quality American so the AC voltage is higher.

Do you guys know If the LarryB Alternator is tested for ACVs before its sent out the door? I would hate to get a new one from him like NAPA and have it fail out the door. THanks,

I recently did a new alternator due to occasional VAC spike and got a new DENSO from O'reilly's. It said it was made in USA. So consider that for the future...

I recently did a new alternator due to occasional VAC spike and got a new DENSO from O'reilly's. It said it was made in USA. So consider that for the future...

See I called my local O'reilly's, and all they carried was reman DENSO. They did not even offer or list a NEW one.

See I called my local O'reilly's, and all they carried was reman DENSO. They did not even offer or list a NEW one.

Like said before you should try staying away from reman alternators. I'd call Larry and ask to have the higher output alt to be brought in. Good to have if you ever have an rv with extra batteries. Source automotive in Clackamas, Oregon (503 654 9004) stocks the higher output Nippon Denso and their prices are a little better too. That's where I got mine.

Like said before you should try staying away from reman alternators. I'd call Larry and ask to have the higher output alt to be brought in. Good to have if you ever have an rv with extra batteries. Source automotive in Clackamas, Oregon (503 654 9004) stocks the higher output Nippon Denso and their prices are a little better too. That's where I got mine.

Yeah I'm defiantly not going with a reman. I'll give them a call Monday and see what they say. Do they warranty the alternator even for a/c voltage? I still cant believe the brand new alt from NAPA was putting out a/c. The problem with them is it still passed there test in the store so they wouldn't warrantee it anyways.

I don't know about their warrantee. I just trusted that it would be a good one which it is. You know, I'd bet some of these testers at the Auto parts stores aren't good meters. I know a cheaper Volt meter almost always shows AC noise too high. We had a thread on this and the guys with the average VM's were showing .30 that sort of higher ACV range. I went out and found a Fluke and suddenly my wifes car and my trucks all showed low AC noise.My old VM works great in every way except the Alternator test, but, there's nothing like a Fluke vm.On Edit........ I don't think you need a 200 amp alternator even with an RV. just keep it simple.

Was the AC noise that causes the surge a problem in the tranny a problem in the 98 12 valves as we'll

Was the AC noise that causes the surge a problem in the tranny a problem in the 98 12 valves as we'll

Yes. Watch this video.