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And therein lies the trouble with an otherwise good idea. When I experienced transmission faults that were eventually traced to EMI, the symptoms DIDN'T happen all the time, and it wasn't possible to tell immediately if the transmission was behaving. I could start it up, and it would act just fine for two miles down the road, and then feel a hiccup.
I've driven the truck on batteries alone, with no serpentine belt connected, so I know that it is possible, even though in my case it was involuntary. With no power brakes and no power steering, you know you've driven something when you get it safely back home. It just isn't safe to drive around a community on batteries alone, hoping that the fault will show up, and then suddenly a neighborhood kid darts into the street out of no where chasing his soccer ball.
On a farm, private property, ok. And like you say, if the fault happens all the time, ok. But the trouble is, some faults don't happen all the time, even though the evidence of their happening sets codes in memory.
I did think this problem was pretty much all the time. If it is intermittent, then I am not sure how you will capture the problem, even using a different alternator.
I came up with this idea after thinking about how I have to deal with AC rippled in RVs I work on, as it can be a considerable problem.
In suggesting this as a possible help in diagnosing the problem, there are a couple of approaches. The classic test and simplest diagnostic for AC ripple is to set your multimeter on DC at a test point, I think in this case the positive on the alternator terminal and the other probe to ground. That will give you the output voltage of your alternator. Then switch the meter to read AC voltage using the same contact points. In a solid system, you should not get an AC reading on your meter.
Initially, I was not thinking of taking off the belt. My thought was to remove the connection safely at the alternator as I think that would basically do the same thing as having an alternator take a complete dump and I could not think of anything that would be harmed, but just using a meter is simpler as long as the meter is capable of measuring very low voltages.
I'll try using my meter on my alternator in the morning and see what I get.
Glad I found this thread! I have had issues with my 02 for over a year after doing some extensive work on it. 3 transmission failures in that time. I'm just installed a Swamps tranny a short while ago. Though it generally seems fine, on occasion it does act up, then go away.
How was it determined that AC voltage was the issue?
The trick is capturing it when it is occurring. And normally the component that is causing the trouble, in this case the alternator is suspect, gets progressively worse (the ripple becomes more and more constant). With RVs AC ripple is very uncommon and as it gets worse, more and more systems get glitzy. I suspect it is uncommon on our trucks also.
As another poster said, the symptoms in the case under discussion here sure sound mechanical in nature.
Here is checking for AC ripple. I just hooked my meter to the battery terminals switching it first to DC volts, then to AC volts. The meter says there is no ripple as the battery is charging which should be consistent through the circuit as the alternator is the only possible source of AC ripple I can think of.
Using alligators from battery terminals to meter
Engine running, meter set to read DC voltage at battery terminals. This is charging voltage at battery from alternator.
Engine running, meter set to read AC voltage at battery terminals. Meter reading of 0 indicates no AC ripple at battery.
After re-reading all the suggestions here i started with getting the battery voltage not running. 12.6v
Then I checked battery volts with engine running to get charging volts. 14.5v
Then i set the meter to AC voltage to see if anything was present. 0.009v. Not much, but something. Maybe this is the culprit since its not zero.
So my next step was to change out my alternator with a brand new 160amp unit that i purchased a few months ago but never installed. After I had to grind the mounting bracket to get alternator to fit i reconnected everything (batteries disconnected for about 20 min) and went to check voltages again. After alternator change i get the following 14.2v when charging and when set to AC volts. 0.00 Wow. Maybe onto something here.
So now that things appear to have changed, lets check the codes in the computer and the previous trans related codes are gone. Aha...things are looking up..... *Note: I did not clear the codes from previous reading. Will disconnecting batteries for length of time clear the codes on it own? I would have thought it would have been stored in memory until corrected. But I did get a keep alive memory error, so maybe disconnecting batteries had something to do with it.
So now with the AC voltage gone, codes gone, lets go for a test drive. Thats where disappointment set it. Very little has changed. About the only improvement i could tell is that it doesnt "grind" the gears as i mentioned before like a manual trans. But it still doesnt shift into overdrive and the torque converter still shifts in and out of engagement. PHOOEY. Well, lets see what codes are stored now after it still acts up...
NO CODES. What the...? How can it act up now and not show any codes? Well, i think ive potentially eliminated the alternator and AC volts as an issue. Must be the wire chafe in the steering column. Pulled the steering column apart and then removed the shift lever from the actuator to expose the wire, had to remove the electrical tape I had apparently put there but forgot. Pics are a little out of focus being so close, but there is no indication of chafing in the steering column for the overdrive wiring.
OK. Strike two. Now although i have had Auto Enginuity for a few yrs now, I have never had the reason to use it so I am not very versed in how to operate it or what to look for. But i just started scrolling thru the options of things to monitor. Low and behold i find the option to monitor the Overdrive Cancel Switch/Hold Switch. Damn, this is just what Im looking for. Pull it up and it appears that it is only a binary indicator, either a 0 or a 1 for whether the switch is on or off. This is based on also monitoring my 4x4 low switch which also appears to be the same setup. I toggle the switches to watch the indicator change on computer screen. It appears to be "ON", meaning the OD Cancel is engaged, which is what I am experiencing. I can press the switch to my hearts content but it doesnt change the indicator here on this screen.
However, I noticed that when I pressed the OD switch and hold it, it changed indications on the screen and appeared to be able to allow the switch to disengage and able to allow the shift into OD. Ok, thats something.
Lets go for a test drive and hold the button in and see if it shifts into OD. So i go for a test drive and hold the button in the entire time. NO CHANGE. UGGGHHHHH... So now what? Lets check the codes again.... Double UGGHHHH.... Still nothing of significance....I didnt grab a screen shot this time, but it was the same as previous screenshot.
Soooooooo..... here i stand totally bumfuzzled as to what is going on. To recap...
1. AC voltage, although minute, appeared to be present. Changed alternator and AC volts gone, but trans still wont engage with OD and TC constantly pulls in and out.
2. There is no chafe on the wire in the steering column.
3. AE indicates that the OD Cancel is indeed engaged but unable to make it un-engage. Press button to no avail. I wonder if the switch itself could be bad? Is this a readily available part at a parts house on a sunday? Dealer only item? Im gonna try and see what i can get at oreilly or autozone tomorrow.
I am completely open to any and all suggestions as I am baffled with my limited knowledge. I was hoping that Mark K may have seen this by now and chimed in as I am eagerly awaiting his thoughts on the matter. Is there any more troubleshooting methods to undertake before I have to take it to a professional. Hopefully I can get a call back from BTS as well to help troubleshoot further.
If your truck was an OBS model, I'd say check your brake/tail lights and see that they're working, especially the 3rd brake light. In their case, there was a faulty ground to the transmission, so it (the electricity) sought the next easiest route, and that was to pull its ground through the brakelights. There's actually a very minimal amount of current flowing through the brake light system all the time. Has something to do with the cruise control system. When a bulb burned out, that flow was interrupted, causing transmission shifting issues. Replacing the bulb did "fix it". But the real solution was to run new ground wires, or clean up the connections on the old ones.
You may very well have a hardware/mechanical failure in your transmission. But the OBS trucks are having issues with wiring as they get older. I wouldn't rule out that as a possibility with your truck. Ground wires seem to be the ones that loose connection. There are other ground wires besides the two off the batteries.
As to checking the AC voltage, would it show up in the cigarette lighter/powerpoint plugs? What I was thinking, take a plug that fits those ports, cut the wires, and hook up a meter to read AC voltage while driving. That way you could monitor it the whole time. When it acts up, you'd have your volt meter right there reading what's going on.
OH WELLLL........ SOOOO MUCH FOR THAT..... Just went for another test drive and something definitely broke inside. No more troubleshooting. Only goes about 15-20mph before something definitely gives way in the trans and rpms shoot up and it sound like HOLY HELL DOG CRAP breaking loose under the floorboard. I had to limp home and wasnt sure i was going to make it. When it shifts, it sounds like hammered dog crap. Thats just my luck.....i replace my factory original that wasnt giving me any issues at 295k for a high dollar BTS unit and it only last 56k miles. I guess we will see how BTS addresses this when I contact tomorrow morning to tell him the bad news. Oh well, thanks for everyones input on the troubleshooting efforts. Ill let everyone know how it turns out. I hope I can get the same results as Ive read about in the past.
I fell for you. I know how it goes. He's just so far. Did you drive out there to have him install the BTS trans? If so, now you have to pull it out and ship it or drive back out. I have a noise in my JW torq converter to. Thing is when I drive all the way out there it's hot and don't make the noise. So John won't replace it. This is even though he new there was problems, that's why he changed them to an ungraded model. From what I've read, BTS will help you out if it's there fault. I've read stories that people from Cali drove all the way out there and he didn't even question it, just fixed them up Of coarse, it was just a shifting thing so he dropped the pan ann changed things out. Good luck, it still could be a sensor that caused this.
I drove out there for the install. Its a good haul, but not like it would be from California or anything, its about 9.5 hrs from my house. Im not sure what will be the course of action, me drive there, me pull it and have one ship to me, take somewhere to pull and ship there....ive heard that he is willing to work with ya, i heard he shipped one to S. Carolina before to change out. But its just a bummer that im even having to contemplate these options. I thought I had the last trans this truck would see....
Called and talked to Brian. He said to ship it to him and he would fix it and return it. I just dropped it off at a local shop yesterday to have the trans dropped. Havent contacted yet to see if they have. Im assuming it would be Monday before it can get shipped, BTS is arranging shipping. With next week being Thanksgiving, Im not getting my hopes up and will be expecting it possibly the week after Thanksgiving (of course while I will be in west Texas on a hunting trip). But Brian was very cooperative and said he would take care of it. So theres that..... will give more when I get more....
My bts broke last October and Brian fixed the tranny and charged me for the parts but he was very busy and I didn't get the tranny back till the first week in December, so be very patient
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