Re: Chrysler dealer tech help needed..
[Re: mopower440]
#1908983
09/09/15 12:43 AM
09/09/15 12:43 AM
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Joined: Jan 2003
Posts: 5,127 Chicago Blackhawks
hemicar1971
master
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master
Joined: Jan 2003
Posts: 5,127
Chicago Blackhawks
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There is no time limit on how long it takes for the PCM to learn with a mopar. Even if you use the Chrysler way of doing it via driving the Vehicle it can take a long time. It took my Daughters Neon 650 miles to learn before it was completely ready to be E Tested. One 2004 SRT4 Neon I own took almost as long to relearn. Others have taken a lot less miles to learn, you just have to wait.
1971 HEMI E BODY REGISTRY
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Re: Chrysler dealer tech help needed..
[Re: mopower440]
#1909497
09/09/15 09:07 PM
09/09/15 09:07 PM
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Joined: Jan 2003
Posts: 2,863 middle Tennessee
mopower440
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middle Tennessee
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I still dont understand why disconnecting the battery would cause this harsh downshift without a quicklearn.. When i first called the transmission shop and told them what vehicle i had and what it was doing, the first thing they asked me was if i had disconnected the battery..I told them i didnt know because i just bought the car, with the harsh downshift. So i bring it to them and they pull a code, 1684 i think, that tells them the battery was indeed disconnected, so they did the quicklearn and it fixed it. So, you mean to tell me chrysler designed this thing to downshift hard enough to rip motor mounts until a quicklearn is done, or,driven unknown miles until it learns to not do that?
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Re: Chrysler dealer tech help needed..
[Re: stumpy]
#1909668
09/10/15 12:50 AM
09/10/15 12:50 AM
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Joined: Mar 2003
Posts: 1,728 ST clair shores MI
moretoys
top fuel
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top fuel
Joined: Mar 2003
Posts: 1,728
ST clair shores MI
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I'll try and make it short. Did they mention anything about your cvi numbers? (clutch volume index) this can tell you the condition of the internals. This measurement basicly measures the volume /space of the fluid between the clutch's,this can indicate worn components. You need a scan tool, read the cvi values,if they are not in spec, you actuate a quick learn,(with a scan tool only) takes a couple minutes, but it basicly resets the transmission and lets the Pcm,tcm and trans learn together again. He might have not charged you anything because they could tell it was worn out inside and you will be back for a rebuild? disconnecting the battery resets the values and takes time to relearn, but if the reading are not at there predetermined value, or off the charts.No telling when or if it all matchs up again. hope all works out for you, Sometimes this is just a band aid fix.
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Re: Chrysler dealer tech help needed..
[Re: moretoys]
#1909954
09/10/15 02:53 PM
09/10/15 02:53 PM
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Joined: Jan 2003
Posts: 27,421 Balt. Md
383man
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
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I'll try and make it short. Did they mention anything about your cvi numbers? (clutch volume index) this can tell you the condition of the internals. This measurement basicly measures the volume /space of the fluid between the clutch's,this can indicate worn components. You need a scan tool, read the cvi values,if they are not in spec, you actuate a quick learn,(with a scan tool only) takes a couple minutes, but it basicly resets the transmission and lets the Pcm,tcm and trans learn together again. He might have not charged you anything because they could tell it was worn out inside and you will be back for a rebuild? disconnecting the battery resets the values and takes time to relearn, but if the reading are not at there predetermined value, or off the charts.No telling when or if it all matchs up again. hope all works out for you, Sometimes this is just a band aid fix. Yes this is right. The adaptive memory of the trans controller will relearn how fast it needs to fill the piston area's to apply the clutch packs. It has pressure switches that tell the controller when the clutch pack piston has stopped moving and has applied the clutch by building up pressure in the clutch area and if it takes to long from worn clutches or seals it will cycle the solenoids faster that apply the fluid and apply the clutch faster or slower and it also learns your driving habbits. It does this to try and make the shifts fast and light so you can hardly feel the shifts. The pump problem is when you first put the trans in gear in the morning you are telling the controller to apply the underdrive clutch and if the pump presure is not up to par at that time when you first put it in gear the controller thinks it needs to apply the underdrive clutch faster and it ramps the CVI (clutch volume index) count up by cycling the solenoid faster to apply the underdrive clutch faster. Well the underdrive clutch is on in 1st , second and third but not fourth. So when the trans downshifts from fourth to third it will apply the underdrive fast and that causes it to hit hard because the underdrive CVI count may be high since it dont apply fast enough in the morning if it has a pump problem. Now when they reset the CVI counts which is what the "Quicklearn" does it tells the trans controller to go back and apply the clutches for a normal new trans and it sets the CVI counts back to normal. So now it apply's the underdrive clutch slower but if it knows by not seeing the pressure switch tell the controller the piston takes to long to move and build pressure then it will slowly start applying the underdrive clutch faster and will in time start applying it to fast and then you will have the same harsh 4-3 downshift. It may take a few days or a few weeks if there is a problem there but the Quicklearm can just be a bandaid until the controller relearns if the clutches need to apply faster. Unhooking your battery should not have caused the harsh 4-3 downshift as that most likely was just building up to that harsh shift over time from either worn clutches and seals or a weak pump. Ron
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Re: Chrysler dealer tech help needed..
[Re: stumpy]
#1910155
09/10/15 08:44 PM
09/10/15 08:44 PM
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Joined: Jan 2003
Posts: 2,863 middle Tennessee
mopower440
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Was told it was gone but he swore it was a update problem not a trans issue. Car was cheap because the seller knew the real problem. But buyer wouldn't believe the trans guys here. calm down stumpy, that aint the way it is..i said i wanted to TRY the update first before going deeper and if it didnt work, then i would take it to a trans shop, and thats exactly what i did. The trans shop did the quicklearn and said come get it and that they see this a lot and the quicklearn in most cases fixes the problem. I didnt say that, they did! And the seller did not know the real problem. He is a friend of mine that just aquired the car from his elderly father. It started downshifing hard and he said he didnt know why it was doing it but he didnt want to spend the money on it to fix it, so i offered to buy it because its in nice shape and i was willing to have it fixed. end of story.. Thats all there is to it. NOW, I thought if the pump was bad you would ALSO get a delayed engagement in the morning when the trans is cold.? Its NEVER EVER done that..If the clutches are bad already, at 109,000 miles with a car thats been this well taken care of, i see why chrysler aint doing to well, even most GM [censored] cars trannys go well beyond 109,000 miles..
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Re: Chrysler dealer tech help needed..
[Re: stumpy]
#1910243
09/10/15 10:41 PM
09/10/15 10:41 PM
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Joined: Jan 2003
Posts: 2,863 middle Tennessee
mopower440
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Not all GM transmissions go that far without troubles. You got one trans that has an issue but what about the thousands of others that have no problems. Just because a bulletin was issued doesn't mean every trans is bad. It just means they have seem that arise in some transmissions and the update can sometimes help but not every time. Do you think that because they didnt do the quicklearn after the update that its a slight possibility thats why the update didnt help initially, or do you think the trans is still bad? I just hate it if its bad because it does so well right now, and even before the quicklearn, it upshifted through the gears perfect, smooth, didnt slip, no delayed engagements...just the harsh 4-3 downshift..
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Re: Chrysler dealer tech help needed..
[Re: DaytonaTurbo]
#1910319
09/11/15 12:16 AM
09/11/15 12:16 AM
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Joined: Jan 2003
Posts: 2,863 middle Tennessee
mopower440
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middle Tennessee
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Ron summed it up very nicely, but the long and the short of it is you will be returning to that trans shop again. Probably sooner rather than later. If it does start again, wondering if i would be better off just buying a low mileage used tranny? Im sure it will be expensive for them to overhaul it.. It will suck also if its ruined just because of the harsh downshift..as i said, it goes through the gears just fine, no slips or anything..Heck, im used to having to replace a trans because it slips to beat hell or completely loses a gear or quits pulling..all this was doing was downshifting one gear harshly..
Last edited by mopower440; 09/11/15 12:17 AM.
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