I have a 2002 Grand Caravan, when foot is on break, speedometer jumps all over, engine bucks so bad I have to put it in neutral or park at every red light.
When I go forward, it jumps a little, and sometimes will not shift, engine reves up so bad, I have to pull over, shut engine off, turn it on and then it shifts.
Speed sensors were supposedly replaced with the plug for them. It is at a dealership, they checked all the sensors, electrical wires, etc, and not it doesnt shift at all!! It is still there, now I have no van to drive. They claim they did nothing to it, it was shifting 90% of the time. It will not shift at all, even when I shut it off and re-start it. Now they claim it may need a new used tranny. I dont trust them. any suggestions would be greatly appreciated.
The dealer would have scanned it for error codes. If you want anyone to be able to get started, find out what error codes were found and post them. That means the very exact and specific code like “P0123” - not what anyone says that it means.
You’re also going to have to report more about the vehicle - like its mileage and everything you can say about the regular kinds of maintenance that has been done on it over its life (as much as you know if used). This means everything beyond oil changes - like plugs and wires and filters, and especially the transmission fluid & filter.
A better description would help too. Presumably the speedometer only jumps all over only when you’re still moving? Or any time you step on the BRAKE, whether moving or not. When were the speed sensors “supposedly” replaced, and by whom? Did the whom check anything or just make assumptions about the speed sensor because of the speedometer? Were error codes pulled then?
You may or may not need a new transmission. But your symptoms are not internal transmission symptoms alone. But keep in mind that you’re asking a bunch of strangers who can’t see or drive or scan etc. the van to comment on what a fully equipped shop is telling you. So you need to be a little more thoughtful about the kinds of info you’re sending out.
I will mention that a lot of those Caravan A604/41TEs have been yanked for want of a good ground strap. But that’s just a completely random note.