Help: Overdrive mode oes not work after transmission replacement

[yuris]

Anybody knows what can cause the following problem: after the 52kmiles old transmission unit has been installed on my Mazda 929 the overdrive mode does not want to work:

1. I can not fix the “HOLD” button on the AT shifter in neither ON or OFF position

2. The “HOLD” sign on the indicator blinks.

3. When I drive the car, the engine does not shift to the 4-th (overdrive) gear.

4. After resetting computer the symptoms 1 and 2 disappear, but only temporarily -- until the car moves a few meters. Then it all (symptoms 1, 2 and 3 combined) starts over again.

Probably, the problem is not a mechanical in origin but rather a failure of some electrical circuits. Mechanic who replaced the tranny has already inspected visually all the electrical connections of the transmission unit but did not find anything wrong.


Anyone can help here?

Thanks a lot!