So my husband just replaced the fluid and filter on our 1994 Plymouth Grand Voyager 3.0L A604 4speed transmission. It's the second time since we bought the van back in December 2019. The first time he also changed the shift solenoid. Fluid level seems to be right and we're using the prescribed ATF+4. We noticed that now it downshifts roughly into 2nd and 1st gears when braking to stop after driving on the highway for quite a bit of time. After shutting it down and allowing it to cool, the problem is gone. It shifts up into each gear smoothly. I noticed that it doesn't shift down as hard if I coast most of the way to a stop. Engaging the brakes seems to make the downshift more noticeable. The van has 107,000+ miles on it and we are only the second owners. There is a shudder, but it has the shudder while parked, so I wonder if it's also got a misfire. I'm not sure the shudder is transmission related but my husband worries that the torque converter is going out. Can anyone help us figure out what to do next please?