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Discussion Starter #1
Hey guys,

a week ago i started the "A604 new software" topic, got some serious information, thank you!

Now a have a few numbers of TCU´s here, which one should i use, or, lets say, can i also use a 1995 model (Acclaim V6) for my 1992 Spirit?

Those are the numbers:
  • 1989 - 91: 4796121
  • 1992: 4796123
  • 1993 - 95: 4686606
AND, something special.....i´ve got a newer TCU at home, numbered 4761846, from an 94´ Acclaim.....but i could not find that number...

plus...the older TCU includes 2 relays on one side, the newer one does not. Are those relays one part with the TCU or changeable?


Can you help me out on this one?

Thank you,
Kevin
 

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You cannot mix 1993 and up with anything 1992 and earlier, there were major changes in TCM electronics at that time. You must adhere to the year/engine limits listed below.
4796121 is the latest reflash for 89-91 3.0L AC,AY,AS,AG,AA & AJ
4761846 is an old flash for 89-91 3.0L AC,AY,AS,AG,AA & AJ
4796123 is the latest reflash for 92 3.0L AS,AA,AC,AJ,AG,AY,AP & MEX A1
4686606 is the latest reflash for 93-95 AC,AY,AS,ES,AG,AA,AJ,AP,A1,A3,A4 &A5 AL

I meant to post this in your other thread if no one else did, but it took some time to find the info on my old computer.
 

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Discussion Starter #3
Thank you ver ymuch, i really appreciate it!

So 4796123 is the one i need, thank you!

That´s the only one i found (year matching)

http://www.ebay.com/itm/1992-PLYMOUTH-ACCLAIM-TCU-TCM-R4761846AA-22-see-item-description-/170914723784?pt=Motors_Car_Truck_Parts_Accessories&hash=item27cb4fb7c8&vxp=mtr

I still got the first one, no heat fins, so if i try the one i listed here, willi feel any difference? Seller says: "Hello, yes the item got a software update on August of 1999 (sticker stated)

This was a re-manufactured TCU from Mopar that has been used."
 

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That one should be ok - it's a newer unit that should be right up to date firmware wise.

You'll have to do some driving around before it adapts to the transmission. IIRC there's no quicklearn function in 1992, but it could have been added to newer TCMs like that one. At any rate, when I got the updated one for the Imperial I just tossed it in and let it learn on its own. Didn't take long for it to adapt.

Those relays should stay with the car and should be part of the harness. No Chrysler TCM I have ever seen has relays in it, and I have quite a few from 1992 in the storage room. They may be bolted to the TCM, but shouldn't be part of it.
 

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Discussion Starter #6
A little update on this one....

Got my TCU today, disconnected battery, installed the TCU, connected battery again, let it sit for a few minutes, then i let it run for a few ones (already operating temperature)

And....disaster. I drove arround for 1/2 hour. Delayed, harsh shifting, upshift to 4th arround 80 Km/h,extremely delayed downshifting etc....

Anyone an idea for this troubles??
 

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Keep driving, it should learn. If it's a used TCM it still remembers the "old" transmission it was attached to. If it's a new one, it likely starts from a default setting. The original TCM had a memory that could be erased with a battery disconnect. The newer ones have a non-volatile memory meaning they do not reset after a battery disconnect. I don't think there will be a quick learn via scan tool available for a 1992 car. Follow the procedure here to retrain it faster:
http://www.allpar.com/fix/trans.html
 

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Discussion Starter #8
Thank you sir!

It´s a used one from a 1992 Acclaim. My car´s a late 1991 model. But no limp mode, just extremely delayed shifting.

I´ll try it right now, give you some feedback in a few hours!
 

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Yeah, it'll be like that for a bit until it learns the tranny.

Edit - wait, it's from a 1992 vehicle? You should be using one for a 1990-1991 car. 1992 doesn't really interchange TCMs with any year but 1992.
 

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Yeah, I hope you mean a late calendar year 1991 car that is really a 1992 model. The difference between 1991 (model year) and 1992 is very important in this case.
 

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Discussion Starter #11
I know, that was my only concern...1990 - 91 is one unit, 1992 the next and 1993 - 95 the last for the AA Bodies.

It´s registered as a 1992, but features tighter power steering, bigger radiator, i guess it´s a 1992 model. A handwritten sign on the old TCM was showing "08/08/91 ...


Now a driving update:

1st - 2nd: Harsh. A classic bump shift.
2nd - 3rd: OK
3rd - 4th: Smooth like butter
TCC: Does not work any more.

4th - 3rd: OK
3rd - 2nd: OK
2nd - 1st: wont talk about that. Like a worn out clutch.

My opinion:

1st: Trans is too worn out to make it "better" than before.
2nd: Wrong TCM


What do you think?

Car was built arround Aug. 1991, here´s the VIN: 1C3XAB632NF182379
 

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VIN indicates you have a 1992.

1-2 and 2-1 should get at least as smooth as the old TCM gave you. Might require some more time yet.
 

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Agreed, the car is a 1992. I agree, it's too early to say the swap isn't working. I'll bet it keeps getting better.
 

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Discussion Starter #14
VIN indicates you have a 1992.

1-2 and 2-1 should get at least as smooth as the old TCM gave you. Might require some more time yet.
OK, yeah just tried the VIN decoder (again), just to be sure.

TCM:



also features a software update from 08/1999


EDIT: 1st - 2nd was, lets say OK before the TCM change, 3rd - 4th was extremly hard, now it´s very, very smoth, even under full throttle aceleration.
BUT, every upshift happens at exactly 4500 rpm. Maybe the kick down cable?
 

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Discussion Starter #15
AND.....i forgot to say, it´s like driving with a complete different vehicle:

Old TCM: Upshift to 4th arround 40 - 45 KM/H
New TCM: Upshift to 4th arround 75 - 80 KM/H (!!)

Why?!

I really sont get it, rpm´s climb up to 2100 - 2300 befora a 2nd - 3rd or 3rd - 4th upshift happens....
 

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There is no kickdown cable on an A604. The differing shift points are part of the learning process. Drive the car hard and the A604 will leanr to upshift at higher RPMs. Baby the car and the A604 will learn to shift earlier.
 

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Discussion Starter #17
There is no kickdown cable on an A604. The differing shift points are part of the learning process. Drive the car hard and the A604 will leanr to upshift at higher RPMs. Baby the car and the A604 will learn to shift earlier.
I tried to, but how long should it take?

Engine was cold on the second try (after diconnecting the battery), so i drove really carefully for around 25 minutes, not higher then 2500 rpm´s.

Tomorrow i´ll do the whole process again, I hope i get some sucess for earlier shifting, curious about that!
 

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You can skip disconnecting the battery. It will have no effect. There is no set time period, that adaptive process is what made the A604 unique.
 

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Discussion Starter #19
Ah OK, didn´t know that it is THAT sensitive!

So if i try just to cruise arrund and baby it, it will learn to react or upshift earlier after some time even if a pretty late shifting period is saved now?
 

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IIRC it took about a week for the Imperial's updated TCM to forget the Dynasty it was in and learn the new transmission. Didn't take as long when I put the rebuilt transmission in, but that's probably because it was still dealing with the same driver ;)

Just give it some more time. Keep in mind the new unit has completely different programming from the original and will naturally seem a lot different in operation. That's a good thing, in this case. I didn't care for the way the Imperial was shifting before I got rid of the old non flashable brick of a TCM, even after I did the ATF+4 flush.
 
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