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Discussion Starter #1
Hi everyone! Before I launch into my problem, some backstory:

My car is a 2003 ford focus see wagon with the 2.0zetec and an auto. A while ago, my car had great difficulty starting. This "while" ended up with my car not being able to start at all at a point, despite the efforts of several mechanics. Eventually, it was started with a new ECU and then carted off for further work/programming.

On picking the car up from the mechanic's shop 3 days later, I noticed a (dried?) pool under where there tranny pan is. I mentioned it to my mechanic but he didn't think too much of it. I also noticed my check engine light was on ( something I didn't think too much of)

However, I quickly realized that it had started shifting funny. On the highway, it felt like it would suddenly drop out of overdrive and continuously rev, try to slam into overdrive and rev again. I also noticed the ECU had stored codes P0755 and P1520. Things got to a head when I suddenly realized it was extremely difficult to go in reverse. ( Only went into reverse after revving the engine and boy, it went violently!). I checked the fluid and it seemed normal. The tranny pan and bell case were however SOAKED So, I panic added a quart- it started to reverse normally after that - though the overdrive problems did not seem to go.


So I sent it back for a transmission fluid and filter change. (I was due for one next month, so yeah) Car ran normally after that. Code was also erased (but ECU was not reset). However, just a day after it started shifting into overdrive funny once again and with same codes stored. However this time I noticed a few things.

1) The car shifts perfectly when started and driven - problem is random, but mostly occurs after downshifting to gain some speed- car seemingly doesn't go back into overdrive again; with the rev- bang- rev routine from earlier.

2) As soon as the car assumes it's "overdrive" problem, all other gear shifts are quite violent (car slams when going into all other gears).

3) everything becomes normal after only turning the car off, then on again.

I would say I have come to suspect a few things.
1. Is my tranny fluid still low? ( Despite the tranny fluid/ gasket change the pan still seems awfully moist.
2. Should I just go ahead and change solenoid B? (The trigger for code P0755). I learn it is not difficult but getting the part may be a challenge- hence my hesitance.
2. Is my new ECU acting up ( it has not been hard reset since the change- codes have just been erased).

However, I am no pro with cars, much less transmissions. On telling my mechanic, he suggested I buy a new transmission - those words made me run to this forum (lol!)

Help would be really appreciated- once again!
Thanks!
 

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Discussion Starter #2
Alright, so some follow-up. On doing some online research, I realized the "new" ECU the mechanic put in is quite different from the one it replaced. The "new" one's part no is 1MSF-12A650-NB; which I came to learn is from an '02 SPI.

The old, ECU however, is 3S4A-12A650-KC, which of course, is from an '03 2.0 Zetec.

I think this might explain the P1520; I learn this code is not applicable for my engine/year model.

However I am not too sure it might be the source of my random shift tantrums since (by my novice opinion) both engines use the same transmission (4F27E). Or perhaps they use different ratios?

I would very much appreciate some expert opinion so that I can go ahead and import a new ecm (if it comes to that).

Thanks!
 
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