I have an 01 Grand Caravan Sport that's been modified with a rear entry wheelchair ramp. I've put a lot of work into it since I bought it in January, but it recently started doing a weird shudder-lurch when stopping. Not every time, but a lot of the time. I took it into Pep Boys, thinking it was something with the suspension (they fixed the sway bar last month) and they drove it and looked at it, but said it was the transmission, and it was going to get worse. They gave me the name of a mechanic I've heard of (my husband used them in another location) to find out what it is.
My question is, what could this be? There is no issue when shifting gears, even though the previous owner mentioned an issue with shifting to 2nd, I've never experienced it and had an inspection done right after purchase that showed no significant issues, mostly hoses that needed to be replaced and routine maintenance that had been neglected. I checked the fluid and it was high, if anything, which my husband thinks could be just as bad as low. There is a weird dry click on the left/driver side that started after they fixed the sway bar, but I took it back to them, and they said everything was fine, so I'm not sure if the two are related. It's not just on turns, but sometimes on straightaways, bumps or flat road, and is random, if that helps know what it is.

I hope I was clear, and if I missed anything, please let me know and I'll try to answer quickly.