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Transmission shifting problem after flush/fill - 2001 Chrysler Town&Country

I took my Chrysler Town & Country in for 75,000 service at my local mechanic (not the dealer). Transmission was already replaced once (by the dealer under warranty) at ~30,000 miles. Everything was working great when I took it in for oil change, trans flush & fill, check belts, etc. I picked up the van & immediately noticed that as I’m slowing down between 30 & 20 mph there is a big lurch/grab/thud. Mechanic said to wait a few days to see if it improved, but no improvement. I called back and they said they had no idea what could have caused the problem & certainly not anything they did. Any idea what could have happened & how to fix? I’m not looking to blame anyone…just want to help them analyze and fix so the van doesn’t die because I really can’t afford a new transmission.

It sounds like its going into limp mode, the computer needs to be scanned to find out why. Tell me something, did the mechanic drop the pan and change the filter before they did the flush??



I’ll have to ask that question tomorrow. Is it really bad if they didn’t? Sounds like you have an idea what could have happened?


Hopefully transman himself will answer as he knows a lot more about this than I - but generally all you should really need to do for taking care of the tranny is drop the pan & change the filter about every 30K miles. I have often heard it said that if a flush is to be done that the filter should be changed first. If it has accumulated gunk, the flush can stir it up & spit it out where it can sort or make a mess of things inside of the transmission.

OK, went to the shop for appt and they said they changed filter & then flushed. They also said a mechanic had road-tested before they did anything and he had noticed it downshifting early at that speed before they touched it. (They never said anything to me about it to me, though, until I came back and told them about the problem.) Owner said it’s a computer problem and needs to go to the dealer for re-programming, & that maybe it’s more pronounced now that they changed fluids but it was already happening. Does that sound right?

No, it does not sound right.

A flush that is not done properly can damage a transmission, and I think that this is what happened. Unfortunately, proving the exact cause will be a problem, but an assessment by an independent transmission shop (NOT AAMCO, Lee Myles, Cottman, Mr. Transmission, or any other chain) should give you an answer as to exactly what is going on.

I think that you need to find a new mechanic.

I appreciate the help. Is it true that only the dealer can re-program the computer, via a link to manufacturer, or can an independent shop do this? The auto shop told me I had to take to dealer.

Is it worth fixing this if it needs a 3rd transmission at 75,000 miles?

I believe that this is true, but then the question arises:

Why did the transmission allegedly need to be re-flashed after this transmission service? You did tell us that it was operating properly prior to the flush, so…

On my 1997 Chrysler T&C we had to replace the transmission module. An independent shop did this and reprogrammed the module while I watched. Everything worked fine afterwards and as I recall the part was between $200 and $300.

One warning I’ve heard many times though is that Chrysler transmissions must have the correct fluid installed (ATF +4). If another fluid is used the transmission won’t work well and can lead to its early death. Some shops use a different fluid then add a friction modifier that is supposed to give it the properties of ATF +4 fluid, but I’ve heard and read that the result is not even close to what real ATF +4 fluid is and again it’s not good for the transmission. Find out what the shop used. Also, as others have said, get the codes read.

I appreciate the advice & answers.

The shop says it had a problem before we brought it in (though they never mentioned it then) that was discovered by their mechanic during a pre-service road test. Apparently he thought it was downshifting early when he did the pre-test (at least that’s what he says now). We never noticed anything until after the service, because it is now very obvious there’s a problem. I think we’ll take it to an independent transmission shop, as you suggested above, to see if they can figure out what’s going on for sure & what it would take to fix it, and if they say we need to take it to the dealer then we will.

The chrysler transmissions are super sensitive to the fluid put in them. Make sure that the mechanic put chrysler trans fluid (bought from the dealer). It probably requires ATF+4, but check the owner’s manual. Nothing else will work.

If it upshifts properly after the problem occurs without having to shut off the van, it’s not “limp home” mode, but “bump-shift”. What happens is the transmission control module continuously adapts to clutch wear and fluid pressure, among other things. As the fluid ages and the filter gets partially clogged with particles, these parameters change very gradually. You then suddenly change these parameters by changing the fluid and filter, and the TCM requires some time to adapt. I think the “reprogramming” your mechanic is referring to is what as known as “quick-learn”. It couldn’t hurt, but the TCM will do this on its own. Exactly how many miles and trips has it been since the problem arose?

Of course, it is possible that something went wrong with the flush, and Steve63 is exactly right about using ATF+4. Is that what they used? Just ask them what type of fluid they used without mentioning ATF+4.

Sorry it took me a minute to respond but as far as the filter goes, yes, it needs to be replaced before the flush is done. Many shops leave out this critical step. That is just way too lazy. As far as the programming goes, no, dealers are not the only ones who can program computers. Independants can do it with the proper equipment. I have flashed many PCM/TCM’s with my Snap-on MODIS and another piece of equipment called a Pass thru Pro. I have accounts with different vehicle manufacturers where I can download updates and flash them into PCM’s.


I called & asked the head honcho. He said the receipt shows what they used. It shows ATF+4. It’s been one week, 386 miles, most trips < 20 miles, one longer trip at speeds up to 65 mph. It doesn’t seem to have improved in that time. No problem on up-shifts or on downshifts at other speeds – only the one between 30 & 20 mph on the way down.

UPDATE: I got the name of a good transmission place, called them up, told him the problem and his first words were, “Is this a Chrysler product?” He pretty much told me the same thing as NYBo did here…fluid changes in Chryslers tend to throw the clutch volumes out in the computer. He said to swing by and in 5-10 minutes he can run it on the computer and hopefully it will be fixed. I’m sure this will be MUCH less than taking it to the dealer, so thanks to those who suggested I try that route. I’ll try to post again to let you know if it works!

I have been reading the opinions and thinking maybe it has the wrong fluid in it, but since Steve mentioned it I will too.

SOLUTION: I took the van in to the local (independent) transmission shop. They re-flashed the computer, it took less than 10 minutes, no problems after that. The guys who run the transmission shop were great – they didn’t charge me anything! (Maybe they think they’ll see me again someday for a full replacement since I have a Town & Country???) Anyway, a happy ending here. Thanks again to the people on this discussion board for all the helpful advice.


See “lets see who gets this one”. Same deal, sort of…