500 Dual Logic Fluid

[Magic Mick]

Hi Folks, I am a Newby from the East coast of Australia. I purchased our/my second Fiat awhile ago. A 500 S 1400cc Dual Logic Gearbox. A lot different to the 124 I had in my 20s. I have been trying to find out when I need to change the Dual Logic gearbox fluid as there is nothing specific mentioned in the service Handbook. Can anyone help with some info please?
Cheers Mick

 

[alexGS]

Hello Mick - welcome to the forum. :wave:
There are two different fluids, the gear oil in the mechanical part of the gearbox, and the hydraulic fluid in the actuator/reservoir assembly.

Neither fluid change is specified as a service item; however, I believe it best to change the gear oil at five years/100,000km. Use Tutela Matryx, or a semi-synthetic 75W90 GL4+ oil (not GL5), Penrite make a suitable oil available at your local Supercheap Auto. The change is straightforward but requires a 12mm Allen key (e.g. as a 1/2”-drive socket bit), to remove the plug under the driveshaft to drain, and the plug on the front of the gearbox to fill. Capacity around 1.4 litres, from memory.

The actuator hydraulic fluid is a type of fully-synthetic ATF sold as Turela CS Speed (as used in Alfa Romeo Selespeed applications) and I would not recommend substituting any other brand - contact your dealer. To change it you would need at least one 1L bottle, but I think I would get two. Again, a change interval is not specified but I would do it every five years, as the golden fluid does become a dirty grey colour.

I achieve this by disconnecting the pipe at the base of the reservoir; open the driver’s door several times to exhaust the reservoir supply, then refill with fresh fluid to the green line. The reservoir is difficult to reach and see; it lives under an aluminium heat shield which is difficult to remove; there just isn’t space! You may need to remove the radiator fan. Definitely make sure that you can remove the filler plug on the reservoir before you drain the fluid from underneath...

-Alex

 

[DavyP]

Just a query. I wouldn't have thought that opening the door a few times would have emptied the accumulator. I know it pressurizes the system , but would have thought that the fluid would have to be exhausted through the system by pressurizing and releasing some of the actuators. This can be done by switching the ignition on without starting the engine and changing from Nto D a few times. Willing to learn though, if it can be done any other way.

 

[Magic Mick]

Hi Alex, Thanks for all the info. Only up to 40,000 & 3 years but I was a bit worried about the cost of a new transmission. I'll save your post. Bought the car for my wife to drive but love getting my hands on as often as I can.
Thanks again.
Cheers, Mick

 

[alexGS]

Just a query. I wouldn't have thought that opening the door a few times would have emptied the accumulator. I know it pressurizes the system , but would have thought that the fluid would have to be exhausted through the system by pressurizing and releasing some of the actuators. This can be done by switching the ignition on without starting the engine and changing from Nto D a few times. Willing to learn though, if it can be done any other way.

By opening the door a few times, I wasn’t meaning to depressurise the accumulator - I was meaning to empty the fluid reservoir so that it could be filled with fresh fluid. The pump runs and empties the reservoir through the pipe that’s disconnected. The pipe is the return from the pump to the reservoir.

If you want to depressurise the accumulator for some other reason, one way is to unplug the pump and make a couple of gear changes. That will, of course, set a fault code, which you could then clear with MultiECUScan. But if you have that software, you might as well run the Accumulator Depressurise routine. Anyway, that isn’t necessary for a change of the fluid in the reservoir.

-Alex

 

[alexGS]

Hi Alex, Thanks for all the info. Only up to 40,000 & 3 years but I was a bit worried about the cost of a new transmission. I'll save your post. Bought the car for my wife to drive but love getting my hands on as often as I can.
Thanks again.
Cheers, Mick

No worries. Bear in mind that, unlike a conventional automatic, a ‘new transmission’ would be in two halves; the ‘manual gearbox’ part, and the ‘actuator’ (often called the ‘robot’) part, which is attached to the outside of the gearbox. You’ve probably seen the cost of a replacement actuator - it’s an all-in-one unit with the pump, pressure accumulator (sphere), reservoir, electrovalves, and hydraulic cylinders, designed to be exchanged as a complete module to repair any Dualogic faults. It even comes pre-filled with fluid, ready to simply bolt into place and calibrate.

This ‘modulisation’ was in answer to problems with workshops not knowing how to diagnose and repair the earlier Selespeed systems satisfactorily, and the long discussion thread running on this forum basically proves that intermittent faults can be frustrating and expensive (in workshop time) to try and solve without replacing the entire actuator.

These days at somewhere between $2000 and $3000, the actuator is relatively good value for what it is; try getting a conventional automatic repaired for that money nevertheless I expect it will be possible to repair the seals, pump, accumulator etc. as an alternative strategy, when the cars are old and worth less than the cost of the complete module. It just hasn’t been practical yet, as it’s all been trial-and-error at the owner’s inconvenience.

Our 2008 500 has just rolled over 120,000km and is still on the original actuator, no faults. I expect our clutch assembly will need replacing some time before 150,000, but we’ll see. It’s a standard clutch, just like you would find with any other manual gearbox.

Anyway I wish you and your wife many kilometres of happy, economical, and reliable driving - as we’ve had

-Alex