I've done some searched on this forum, and i haven't seen my issue listed, if it's already in a thread, please let me know, but here it is...

98 Gr Voyager, approximately 120K miles. I had never had the transmission serviced before, but after doing the 100K tune up, i started thinking that this van could last a while, because it was just humming along, running VERY well.

So...at about 110K, I had the transmisssion serviced. Since then, it starts "jumping" once it gets warmed up, and it's doing it at high speeds on the freeway. We will be cruising along, and it jumps down a gear and then jumps right back. There's some noise associated with it, but I wouldn't call it a "clunk".

My fear is that they flushed the system when they serviced it, which I have heard is a no-no, but wanted to post my issue here and get some thoughts. This forum has been very very good to me over the years with this van, and saved me a lot of money.

should I just bite the bullet and have the transmission rebuilt, since it has 120K on it? I think I have found a shop that I can trust to do the job right.

Ya, you're taking a chance on a flush especially on a higher mileage van which, is when most think is the time to do it. Ask them what fluid they used. Should have been ATF4. If anything else is in it get it out.

OK...i called the dealer where the service was done.

He stated that the work order shows ATF fluid, and he said that it doesn't specify ATF4, but that they would use the standard fluid that the book specified. Typical answer, i know, but that's the answer that I got.

he also said that he didn't think that ATF4 was available when that van was built, so he didn't suspect that it would be required, therefore...

What's the difference between ATF and ATF4?

Can I assume this was a Chrysler Corp dealership? If that's the case, I'm a bit puzzled. Your minivan originally required ATF3 transmission fluid. As of around two years ago, according to what I've read on several forums and in a couple TSBs and what I've seen in stores, Chrysler stopped using ATF3 fluid and required the use of ATF4 fluid in any vehicle that previously required ATF3 fluid. That included older minivans. It would seem to me the answer they should have given you was a simple "ATF4" fluid even if it wasn't printed on the work order.

There could be several answers to this mystery. I would bet you talked to someone working behind the sign in counter at their maintenance garage. He or she may not be up to speed on ATF requirements and simply went by what was printed on the work order. I'd like to say considering this was a Chrysler dealership (???), they used the correct fluid. Personally I would nail this down by talking with the tech that changed the fluid or at least the maintenance supervisor. If they somehow used ATF3 fluid then fine and dandy.

I am concerned because at one time Chrysler advocated the use of Dexron fluid in minivan transmissions as a substitute for ATF3 fluid. Later experience revealed that was a poor decision by Chrysler (say it isn't so!). Dexron fluid created symptoms similar to what you are seeing. If there is any doubt to what fluid is in the van I would have it pumped out, not drained, and replaced with ATF4 fluid. Draining only replaces 1/3 of the fluid at best.

the dealership that has done all of the work on this van that i cannot do has had a LOT of turnover in there since I was there last, and they have gone to "service managers", rather than allowing you to talk directly to someone who actually knows what they are talking about.

I'm thinking that it IS the fluid at this point. I have been driving it all weekend (it's my wife's van) and the "jumping" is happening during climbs, or when taking off. Basically, when it's shifting gears. I have no reason to suspect that there's anything wrong with the tranny other than 120K miles of wear and tear.

You recommend a flush, though? I've had people tell me don't flush it, because you could cause things to get in the gears.

She's also claiming that it still dies from time to time when she's decelerating. I have already pulled and cleaned the IAC, and it's happening LESS, but still happening. I'm not sure if the stalling has to do with the tranny or not. I don't see where it would, but thought I would mention it here. I haven't had it stall on me since I cleaned the IAC.

Thanks for all your help, RIP. If you were my mechanic, I'd take you out for a beer every now and again, and you would get a Christmas card from us. Your efforts here are certainly appreciated.

To flush the tranny I have taken off the output fluid line to the radiator tranny cooler from the transmission put a long hose to tranny and starting engine pumping the old fluid into a gallon milk container watching how much you have in the jug and shutoff engine pour back in new ATF+4 fluid and repeat the process until you are sure that all old fluid has been removed. This will remove the old fluid from the converter also. Usually you can do this procedure with 10 to 12 quarts of fluid which you can get at Wal-Mart for about $4.50 a quart. If possible a helper will make it easier.

[QUOTE=triplethreattt]You recommend a flush, though? I've had people tell me don't flush it, because you could cause things to get in the gears./QUOTE]

No I don't recommend a flush. As I said have the fluid pumped out. Tempfixit, though he calls it a flush is describing the procedure I would do. In the procedure he describes, no additional pressure is applied to the fluid, it's simply pumped out under it's own pressure.

Thanks. You can't buy me a beer but, what you can do is next time you get a chance to help somebody, please do. :cheers:
__________________

OK..i had the fluid pumped out, and the service center where I took it replaced the fluid, and put an additive in the fluid that they called "Shift Modifiers".

it ran great for a few weeks, but it seems like it's starting up again.

Not sure if it's related (l'll start a new thread if not) but the engine will just die after it's been running for a while. Always at a stop (or slowing down) it will just die. I can restart it and tool around with no problem, but it's getting annoying. I have replaced the IAC, and the air filter. Any other thoughts? Could the 2 problems be related? I did the key dance, but there aren't any codes present.

i've been perusing the boards today, and I'm wondering what symptoms I would see if the input/output speed sensors were going bad, as well as what symptoms I would see if the transmission control box were going bad, and how much are those parts/difficulty to replace?

Sounds like you need the codes read by a scanner.

Also, take a look at:
http://www.automotiveforums.com/vbulletin/showthread.php?t=906855