99 breeze jars real hard on upshifts sometimes

I've got a 99 breeze with a 2.0 and 140,000 miles on it. It doesn't slip at all. It seems like it shifts a little late but have been told that's just a chrysler thing and I'm used to GM and Ford. I'm about to pull the trans to replace a rear main seal. I need to know if I need to replace the converter while I have it off. It jars the car real hard on upshifts. No particular gear upshift, it's random. It's also not constant. Maybe about 25% of the time. So does this sound like a converter or something else. The car also vibrates pretty bad whether in gear or park, probably mounts but could the converter do this too.

I have a 2004 Sebring with the 2.4L and 20k on it it does that same thing, so I brought it to the chrysler dealership and since it is under warranty they are fixing it. The Transmission pump inside the tranny was bad I guess, just glad that it did it while under the warranty.! I hope this helps it would do the exact thing that yours is doing!