My wife has a 95 chrysler town and country. We got it used. Six monthsn after we got the ransmission statred slipping around 30 or 35 mph. It was like the van would just go into neutral, take your foot off the gas and it would work properly when the gas was reapplied. I took it to two tranny shops. Both said there was nothing to do but wait for it to die. Four years and 25000 miles later it is still running. while the slipping problems seems to have stopped, it developed a new quirk. Every 4 or 5 months when entering a freeway, it will not shift into overdrive. Hence 5000 rpm at 55 mph. I’ll exit the freeway. Get to a safe spot. Turn the car off and restart, the problem will be gone and if i drive on the freeway it will shift normally. Any ideas would be appreciated. It has a few other issues ac, struts etc. If the tranny is going out why fix these things? On the other hand if there is still life in it, maintaining is cheaper than replacing…
Chances are its going to limp mode. The problem is that those things are really complicated and trying to diagnose without a scanner would be like finding the proverbial needle in a haystack - any very large number of things can send it to limp mode.
At the very least, there is a main ground strap for it that has created its fair share of (often misdiagnosed) problems. I forget exactly where it is, but its just a typical black ground wire with an eyelet terminal that’s on one of the bolts on the transmission. Its in the front of the van connected on the radiator side of the transmission. I’d pull that off, check it, clean it up well & put it back.
Short of that you need to get someone with the right scanner when the trans is acting up.
Is the check engine light on?
I think cigroller is right about limp mode. My 90 Dodge Grand Caravan 3.3L, started doing exactly the same thing two years ago. I presume you have the same transmission. It was intermittent, I managed to drive home across the Mohave Desert, 1200 miles, with only two or three incidents. Mostly I drove the whole way at 50mph max and it stayed in OD. Once at home, I had it scanned at my local transmission shop which found the problem was the speed sensor - either dirty or failing intermittently. The shop told me it would probably work fine if I just cleaned off the deposits, but I didn’t bother. At a price of $33 for a new one, and a reasonably easy DIY job, I bought the sensor and changed it in 30 minutes. Solved the problem.
If you were pleased with either of the shops you consulted previously, you might choose to do the 30k trans service now (pan drop to change fluid and filter) and have them scan the unit while you’re there. If you’re lucky, it’s the same sensor, and at that point, with the car on the lift, the labor cost to replace that should be minimal. Like others on this site, I’d encourage you to choose a local independent shop rather than a chain operation. I hope your problem is resolved just as easily!
This is what I will do. Scan ECU for transmission codes-good scanner needed. Also pan drop and ATF/filter change as mentioned. Make sure you use ATF 4 which is what the car calls for. Don’t settle for additives with generic ATF. Then unhook all connectors to the transmission and make sure they are clean & tight. One thing on these that could have intermittent issues is the solenoid pack, which is a relatively easy fix. Check on allpar forums.