I have an '01 Grand Caravan 2WD with the 3.8L and 4 speed transmission with 147,000 miles on it. It's been a pretty good car all together. A couple of years ago, it went into limp mode and threw a few codes. Checked on here, replaced the solenoid pack on the transmission myself, and she ran like a champ ever since.

Today, with no prior symptoms, she started thumping hard when up shifting to 2nd with a little shudder right after the shift. Everything was then fine until it shifted up to 3rd where it repeated the problem. Interestingly, it did NOT have the same problem shifting up to 4th or down shifting at all.

I drove straight home, and as long as I was able to keep it moving and drive easy to keep it in high gear, there was no problem. But every time I had to stop at a light, the same thing would happen again: big thump/shudder going into 2nd, big thump/shudder going into 3rd, smooth into 4th.

I have no engine light on this time, but I still used a scanner to check for codes anyway and found none. I checked the fluid level and it appears just right and the fluid is still pink/reddish and neither looks nor smells burnt in any way. I suspect one of the first suggestions will be to take it to a transmission shop to check for transmission codes, but it's Saturday afternoon, and I may have to wait until Monday to do that.

I'm not a mechanic at all, but like to work on my cars when I can and am fairly handy with a wrench if I've got a general idea about what I'm doing. I don't know a thing about transmissions though beyond changing the solenoid pack myself which went fairly easily. I have searched the archives and haven't found anything that looks like it's on point. After reading many posts though, I will pull the input and output sensors to check for wiring issues or metal debris on the sensors when the engine cools off. Would dropping the pan and changing the filter and trans. fluid likely help any (it's never been done). Other than that, does anyone have any other information or idea that might help over the weekend?

THANK YOU ALL!!!

 

Sounds like somthing is going on in the transmission and I don't think it good. Sorry, I think the planetary is starting to come apart. Once you find out if you have any stored codes, also ask what the CVI readings and post your findings.

 

Too many threads just end without any info on how it resolved, so I thought I'd update this one just to finish is off.

I couldn't wait until the tranny shops opened on Monday, so I dropped the pan, changed the filter, and replaced 4.5 quarts of good, fresh ATF+4.

When I looked in the pan, the fluid appeared to be in surprisingly good condition for 147,000 miles. It still had a reddish color, no burning look or smell, not cloudy or murky, and not really even dirty. The grease around the magnet clearly had some fine particles in it, but when pinched between my fingers, no particles were big enough to feel. The only metal I found in the pan looked to be the small end with the hole in it off of a snap ring. The bit didn't look big enough to even cause whatever ring it was to fall off.

I drove it very easily around the neighborhood a few times, and it felt like it was shifting very smoothly. I got sidetracked Monday, but Tuesday I took it to a shop for a transmission flush/refill. It wasn't a tranny shop, so they didn't have the equipment to look for any transmission codes. But, it has been running very smoothly ever since, so I never took it to the tranny shop.

I won't be driving it on any long trips for a while. At least not until I've got a little more confidence that the transmission is not going to explode. But, for now, it running well.

By the way, my wife told me the thump/shudder wasn't a very good description of what it was doing. She said it felt more like you hit a pot hole when it shifted. I realized she was right because that's actually what I thought had happened the first time. It was when I hit that same mysterious pot hole everytime it shifted from 1st to 2nd and from 2nd to 3rd that I realized that the roads weren't actually that bad. Anyway, she was right, so I thought I'd add her more accurate description in case anyone else has a similar problem in the future.

 

That little piece of metal, was a piece of a snap ring. Should I just end it here.................Just kidding. The snap ring holds the low/reverse accumulator cover in the transmission case above the valve body. In time the o-ring seal on the cover will roll and you may lose forward and reverse gears.

 

In my opinion you should consult a specialist so that THE problem is correctly diagnosed and treated. I guess if you try on your own you may damage your car. I hope you have a good day driving.

 

Thanks for the info. Is there only the one snap ring in the entire transmission? If so, it should be easy for the shop to find. I'll take that info to them when I have them look it all over. Thanks again.

 

There about 10 snap rings in the transmission.