Have just spent last 2 days with EXACT same issues and uselessly trolling through the usual suspects.
You actually have 2 faults
1/ The Accumulator - it will have a tear in the diaphragm allowing fluid to seep in BEHIND the
bladder. So when you run the Selespeed there will be a quantity of fluid trapped behind the
bladder INSIDE the accumulator itself. So after you park it over nite, the accumulator
depressurises and the trapped fluid now over fills the already full reservoir.
Solution - New Accumulator
2/ Now, the gear selection, it could be the RANGE Sensor, the one on the FAR BACK
of the Actuator, right in front of the drive shaft. You can try cleaning it, swapping it with
another sensor, or just replacing it.
I tried all those, to no avail, hell I tried EVERYTHING! So I started over going through all the diagnostic tests again.
When I did the engagement pin securing screw diagnostic, . . . for the first time ever . .. . IT FAILED !! :Shocked:
Yep, when I checked the Pinch bolt, the last "supposed" Alfa Specialists had only done it up hand tight !!! I was able to remove it with just my fingers !!!
New treated pinch bolt, torqued up per specs, EOL carried out . . . . Perfect, working as new.
Also something to watch out for that caught me out and had me absolutely buggered at the time . . .BATTERY VOLTAGE!!!
All the diagnostic work and testing really saps your battery, and mine actually at one point got so low it "collapsed" to 9.00v.
First thing I knew was I had Airbag, ABS, EOL, SOS and every light come alive!! I thought I must have "arced" the battery terminal when I last connected it. Then I went to start the car . . .All I got was two loud CLACKS from the SS and silence.
As I was pouring gasoline over the car to use it as a funeral "Pryor" I went to put window down. . .. ohhhhh sooooo sloooow . . the penny finally dropped!