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420A 420A Auto trans problems.

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spyderdrifter

10+ Year Contributor
5,267
711
Jul 11, 2009
Somewhere in, Colorado
After buying my current car, the auto trans failed. I installed a new torque convertor, and it was fine for a few hours and then the trans wouldn't engage any gears. It started whining, so I replaced the trans pump. I just got it all back together this past week. No change, other than the whine was now gone. Still no gear engagements. So I replaced the solenoid pack with one I pulled from the salvage yard a few weeks ago. Had success and the trans finally engaged. I left for a test drive and when in reverse, the car bucked back and forth, but reluctantly backed up. The forward gears felt fine, mostly. So I decided to drive my car home (been working on it in my parent's garage). During the 5-ish mile drive, I had to stop once because the transmission started making an odd noise, which I don't remember what it sounded like, and the drivability changed a little too, don't remember that either. I figured this was all caused maybe by low atf level. I thought this because the trans dipstick wasn't really giving the greatest reading since the fluid was sloshing around. I checked it after shutting it off, and it even read low. However today I checked the dipstick cold and it shows WAY too much. I drove it at one point for another test drive. Seemed fine, although the trip was short. But when I returned home, reverse was doing the same bucking crap, but almost wouldn't move backwards. I had to rev the engine higher than normal just to get the car to move, and even then it was maybe a foot at a time. The car never stalled, or gave signs of trying to stall, but after moving back a foot, I'd have to push the throttle again and rev high again to move it back. I can't find any info anywhere on this forum regarding this Chrysler A604 trans. I've googled and haven't found conclusive results or solutions. Right now, my only thoughts is somehow the atf level is playing part of the issue, and the other possibility being the solenoid pack since I don't know how great the condition is.

I'm using ATF+4 fluid before anyone asks.

If I can't figure this crap out, a manual conversion is my next course of action since I hate automatics anyway.
 
I have checked the fluid while it's running, but it seems to indicate low, yet it shows too high when cooled. I have read about the solenoid pack needijg a reprogramming, but can be done without thd need of going to a dealership, but can't find it fully explained.
 
It's should be the opposite. Show low when colder and higher when warm. Fluid expands when warm. Whatever the level shows when it's up to running temp. Always go by the lowest level on both sides of the dipstick. They can be programmed without going to the dealer but, a scanner is necessary. Did it all the time when I worked for AAMCO transmissions
 
It's should be the opposite. Show low when colder and higher when warm. Fluid expands when warm. Whatever the level shows when it's up to running temp. Always go by the lowest level on both sides of the dipstick. They can be programmed without going to the dealer but, a scanner is necessary. Did it all the time when I worked for AAMCO transmissions
What kind of scanner? Doubt my Blue Point scanner would do it.
 
After buying my current car, the auto trans failed. I installed a new torque convertor, and it was fine for a few hours and then the trans wouldn't engage any gears. It started whining, so I replaced the trans pump. I just got it all back together this past week. No change, other than the whine was now gone. Still no gear engagements. So I replaced the solenoid pack with one I pulled from the salvage yard a few weeks ago. Had success and the trans finally engaged. I left for a test drive and when in reverse, the car bucked back and forth, but reluctantly backed up. The forward gears felt fine, mostly. So I decided to drive my car home (been working on it in my parent's garage). During the 5-ish mile drive, I had to stop once because the transmission started making an odd noise, which I don't remember what it sounded like, and the drivability changed a little too, don't remember that either. I figured this was all caused maybe by low atf level. I thought this because the trans dipstick wasn't really giving the greatest reading since the fluid was sloshing around. I checked it after shutting it off, and it even read low. However today I checked the dipstick cold and it shows WAY too much. I drove it at one point for another test drive. Seemed fine, although the trip was short. But when I returned home, reverse was doing the same bucking crap, but almost wouldn't move backwards. I had to rev the engine higher than normal just to get the car to move, and even then it was maybe a foot at a time. The car never stalled, or gave signs of trying to stall, but after moving back a foot, I'd have to push the throttle again and rev high again to move it back. I can't find any info anywhere on this forum regarding this Chrysler A604 trans. I've googled and haven't found conclusive results or solutions. Right now, my only thoughts is somehow the atf level is playing part of the issue, and the other possibility being the solenoid pack since I don't know how great the condition is.

I'm using ATF+4 fluid before anyone asks.

If I can't figure this crap out, a manual conversion is my next course of action since I hate automatics anyway.
When swapping the parts where they properly placed. If so it may be a faulty part
 
Everything has been reinstalled correctly. I made triple sure of that. I know how touchy auto transmissions can be, and hate messing with them, so I make absolutely sure before reinstalling them ;)
 
Sorry to hear this. I don't think anyone saw that coming.

For all the upcoming effort, time and cost of a manual swap, have you priced out a rebuilt auto? With a warranty?

Since this is your daily, it might be the least hassle.
 
Nope, I want nothing to do with another automatic. I'd still rather have the manual and have the one extra gear for the highway. Plus I can find parts cheaper for the swap than paying a bit more for another auto.
 
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