4l80e problem

I was told my 3500 cube van 1998 350 vortec with 4l80E tranny was fuc*** as it wouldn't engage 3rd or 4th gear. SO I buy a used one that I know worked before I installed it and guess what.. Same thing. SO either the
tranny shop screwed me with a false conclusion or I screwed this installing it WHICH I doubt. Is there a computer or relearn procedure or is it all controlled by computer ?.. Is there any test's I can do to figure what is wrong ?.. Thanx for any help or advice
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wrote:

The E on the 4L80E stands for electronic controlled. Do you bother to check for erro code before you pulled tranny. I scanned a truck the otherday that was acting weird with tranny and it returned several error codes related to tranny control soleniods or their circuits. I also had a freind that had a 4L80 that was not shifting right and it turned out to be a bad engine coolant temp sensor. When he replaced it all was well. ----------------- TheSnoMan.com
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no codes came up when scanned.. they said it was a bad transmission. The new one is doing the same thing. I'll try and rescan it but no codes are coming up/

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I had the same problem. I had a false code (54?) that was setting due to a bad ignition switch. It would stay stuck in 2nd gear. May check or replace the ignition switch.

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I have NO CODES ! I scanned it, drove it , the n rescanned, THEN undid batery cable drove it and still no codes. I'll try the ignition switch..

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