Hello everyone, I have a 2003 Stratus Sedan 2.4 A604 transmission. My problem is I have a very harsh 4-3 downshift, everything else on the trans works like new, smooth upshifts, smooth lockup and smooth downshifts except for the 4-3 shift. It happens when decelerating and I hit about 30MPH, If I switch it to auto stick mode and manually put it in 4th gear then shift down to 3rd it's even worse, at any speed and any throttle position, tried from 20mph up to 70mph, same thing, just a huge thump, kind of like the wheels locked up for a millisecond and the dashboard makes a cracking sound everytime from the jolt.
Anyways, this started happening a couple days ago, the transmission had 197k miles on it so I figured it was probably worn seals, maybe a pump failure, fluid breaking down, I'm wasn't sure. I understand as much about how the insides of transmissions work as much as I understand how women work. So I pulled a used transmission out of an 03 PT cruiser at the junkyard with 90k on it, got the torque converter from it too all for $50 thinking this would fix the problem. Well it shifts like new now, no more mildly harsh shifts or harsh lockup like the old one, but that harsh 4-3 downshift problem is still there on this second trans also.
Now I'm at a loss, could it be possible that the second trans also has the same failure as the first one did even though every other shift on it is flawless, along with all new fluid and filter, or could it be something external to the transmission like a sensor, wiring, maybe even the solenoid pack? I haven't heard too much about pump failures on these units but maybe low fluid pressure, I have no idea. All the sensors and solenoid pack came with the second transmission and I didn't touch them, but the wiring harness is the same old one.
No codes stored, at least with the key trick.
Once it downshifted to 3rd all by itself at about 50MPH when I was going around a bend, wasn't in autostick mode.
The speedo was working perfectly the whole time, never saw it jump around or drop to 0.
Drove it about 40 miles so far with the new transmission in, highway and city.
Never went into limp mode once, the auto downshift to 3rd was weird but upshifted after a few seconds.
Hopefully I added enough information here, always better to have more than not enough I'd say. If anyone has any ideas where to look or what causes only a 4-3 hard shift when everything else works perfectly, I would really like to know.
Thanks for your time and reading all that.