I have been having issues with my cars dualogic. I didn’t want to pay dealer prices appox$6000 Australian to replace the dualogic in a 2013 car.
My car would not engage gears, message said check hand book.
Though when it was drivable, it would shudder, and drop into neutral. It was really unsafe on main roads. Eventually it just stopped wouldn’t engage gears.
I though that truly the dualogic can’t be this complex to repair.
So I bit the bullet went to a local wreckers and bought a secondhand unit. I benchtested it and there was fluid leaking out of the solenoids, and as well into the front shaft position sensor.
I though there’s no harm in dismantling it. After disassembly I identified that numerous I rings had shrunk on the solenoids and on other places where the seals should seal.
I did notice that at the front of the dualogic unit there is two hoses which connect to the selespeed reservoir bottle, one of these is a weep hose that comes from the bottom half of the dualogic unit.
This was obvious as there was a lot of dried up oil residue on the outside of the unit.
Please note I have great mechanical skills though not so much with hydraulics
I did take out the horizontal position pistons, and the seals. were heavily deteriorated.
I figured that these were leaking along with other o rings, hence that the hydraulic fluid pressure is bypassing o rings and not going to the correct piston. Meaning that the pressure flow of the fluid is influencing another solenoid that should be closed rd or open depending on gear.
This I figured was causing juddering due to incorrect positions because the hydraulic pressure is back flowing ti where it should not be going to, causing gear change issues, dropping out of gear, due to the appropriate internal channel way to be starved of hydraulic pressure or over pressure due to back flow.
This causes the sensors to fault, and trip and throw codes.
I totally dismantled the dualogic and took all the o rings out of the unit, including taking out the clutch piston and sleeve.
I then went to my local industrial o ring shop and had matched up all new o rings and piston seals. The two horizontal shaft position piston seals are an uncommon size and I had to get these custom made.
All up for about $100. Aud I got all the o rings.
I then fitted all the rings to their correct positions, and re-assembled the unit.
Lubing the rings up with Penrite ldas fluid.
I reassembled the unit, and then bench tested it, I tested the pump, it rand for about ten seconds and stopped, the unit retained pressure.
I then tested the solenoids and they all clicked.
I observed the unit for a couple of days looking for oil seepage there was none.
As I didn’t have the fiat software to recalibrate the installation of the dualogic to the gearbox I took it to a local Alfa Fiat workshop as I doubt a genuine service centre would be willing to fit a customer reconditioned dualogic.
The mechanics were awesome, and reinstalled my rebuilt unit, re calibrated it and did a few other jobs on the car, total was about $1900 for the whole job including the secondhand old dualogic and the o rings.
Now the car drives I would say better than new, the gear changes are as smooth as silk, it doesn’t just bang into gear as it did previously.
I tested the pressure and after sitting overnight once the drivers door is opened the pump only runs for about ten seconds to prime up.
I really think that a large majority of issues in the dualogic is due to old and dry o rings not holding pressure.
If anyone in Melbourne or Australia needs one rebuilt let me know. I have a spare I can change over.
