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  #1  
Old 04-11-2010, 02:30 PM
dgc333 dgc333 is offline
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Default PT Cruiser Tranny Question

Last weekend I changed the tranny fluid and filter in my wifes 03 PT GT. I used mopar brand ATF+4 and this is the second oil and filter change the first being at 35k miles, I have just shy of 80k.

Anyway, now as you slow down to a stop the tranny will abruptly down shift to first gear at about 2 mph. It didn't do this before the change and all other shifts up or down are fine.

Anyone got any ideas what might be going on here? The filter just snaps onto the valve body with plastic nubs on the filter body, I was thinking could it be the filter came loose when putting the pan on and it is sucking some air when the fluid sloshes forward under breaking?

I plan on dropping the pan again an taking a look, but I hate to waste 5qts of ATF+4.
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Old 04-11-2010, 08:45 PM
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nhdriver nhdriver is offline
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No need to waste it just get one of those large plastic pans they sell at most hardware stores & reuse it.
I changed my fluid in my PT at 30K & 60K and it still failed at 90K (I used +4 fluid too) Good luck w/ your trans. I hope it lasts longer then mine did.
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  #3  
Old 04-12-2010, 12:45 AM
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Stoga Stoga is offline
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Shifting down when you slow down isn't unusual, maybe how it shifted changed a bit after the fluid change.
For what's worth, the original transaxle in my 2000 Grand Caravan lasted for 163,000. I always changed fluid and filter every 30K miles.
It would have lasted longer, I expect, but I beat on it pretty hard, even tearing the transmission pan and side pan up at least once.
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Old 04-12-2010, 05:46 AM
dgc333 dgc333 is offline
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It's the way it is down shifting. Before you had to be paying attention to notice the shift. Now it's very abrupt and there is no ignoring it.
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Old 04-12-2010, 08:46 AM
19N 19N is offline
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If i recall right, and your tranny is a 4 speed overdrive, this tranny usees CVI "Clutch Volume Index" to create proper shift points. When the filter is replaced the fluid will flow at different pressures, especially if the filter was getting plugged. If possible you can break open the plastic cover from the tranny filter and look at the filter media. If there is brown clutch material in it it could be from the lock-up clutch in the torque convertor ( have replaced quite a few in PT's). After I replace the filter and fluid in the transaxle I hook the scan tool up and reset the CVI and perform a battery disconnect. I have ran into this before when forgetting to clear the CVI. I think if you disconnect the neg terminal from the battery for 1/2 hour ( might take this long to discharge capasitors from PCM and TCM) then hook it up and drive at different speeds it should take care of your issue. Hope this helps.
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Old 04-12-2010, 12:58 PM
dgc333 dgc333 is offline
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Thanks a bunch! I will give it a try.
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Old 04-15-2010, 01:05 AM
mopartec mopartec is offline
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pay close attention to your down shifts. make sure it is not a harsh 4-3 down shift.there are a couple of tsb,s. Tech Bulletins (NOT RECALLS) about reprograming the tcm/pcm for harsh 4-3 down shift and also a pump isssue thats can cause harsh 4-3 down shifts and delayed engagment.drive the car in drive up to 55 mph. then come to a stop normally. the drive the car in 3rd up to 55 mph the come to a stop stop normally. if you feel hard down shift in d and it is smooth in 3rd. then you have harsh 4-3 down shift and need the tcm/pcm reprogrammed.if you have delayed engagement then youll need a pump.
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Old 04-15-2010, 08:36 AM
dgc333 dgc333 is offline
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It's a harsh 2 to 1 down shift and it only started after changing the fluid and filter. I tried 19N's suggestions and it didn't help.

I have been so busy at work I have not had a chance to drop the pan to make sure the filter didn't come loose.
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Old 04-19-2010, 07:55 PM
mopartec mopartec is offline
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a loose filter will not cause that at all.a loose filter may cause delayed engagment when cold. slipping in and our of gear going around corners or going up and down steep hills. you may have to have the trans quick learn to relearn the C.V.I,s. there also have been some isuses with hard 2-1 that i have been involved with that Chrysler enginering has had me replace both the valve body and t.c.m/p.c.m. they say they dont know why it does it.wish i could be more helpful
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Old 04-19-2010, 10:27 PM
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KSTripleMstr KSTripleMstr is offline
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It needs Quicklearned......like 19N was saying the CVI's are now skewed, what happened was when you installed the filter and the fresh fluid and started it up and shifted to drive the filter and pump had yet to prime, The UD (underdrive clutch) CVI is updated when the trans is first shifted into gear, with that pump not being primed yet the TCM just sat there and counted increasing the "known" amount of fluid it needs to apply that clutch....now that the system is Primed that amount is too much. It will eventually go away as it relearns by driving, but if you want it gone quick It will take the DRB at the dealer........In the past I have unplugged the TCM and then drove them to update the CVI's but I havent tried it in awhile. might give it a shot.....If so The TCM is located behind the LF headlamp, have to pull wheel and wheel well insert to access it, has a 8mm bolt in center of connector.
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Old 04-20-2010, 07:32 PM
dgc333 dgc333 is offline
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I tried disconnected the battery and did a code reset even thought there were no codes with no change. We went away for a few days and I haven't gotten back to it.

I will see if my son can borrow the DRB from the dealer he used to work for.

Thanks for the input.
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Old 06-09-2010, 07:23 PM
dgc333 dgc333 is offline
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I just realized I never gave and update to you folks that gave me some suggestions.

After playing with it some more I was wrong about the 2-1 down shift it was actually 4 to 3 I was fooled by how slow you can be going before it will down shift. I confirmed it by playing with the autostick feature and could make it happen at will by forcing a 4-3 down shift and it wouldn't do it on any other gear.

Anyway, would up have the transmission control module reset at the dealer. All is well now and the shifts up and down are smooth as silk.
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  #13  
Old 06-10-2010, 01:17 AM
mopartec mopartec is offline
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glad to here that its fixed.for some reasons the programs keeps tightening up the cvis and causing hard 4-3 downshifts. the flash and qick learn fix that.
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