Join Date: Jul 2007
Location: New Zealand
OK, well, my take on it while we wait for Smaky (pronounced Smack - e, apparently!)...
The accumulator is probably fine (unless the pressure is acting up). I don't think a faulty accumulator will cause an ongoing loss of fluid. As, err, 'wankski' said, the accumulator stores pressure (it is a pressurised gas sphere) - so if it loses its gas, it will fill with fluid instead, but once it's full, the fluid level won't go down any more (and, the pump won't work properly, the reservoir may suddenly overflow in certain conditions).
Meanwhile it IS possible for the Selespeed to leak into the gearbox, even though they are supposed to be separate systems. The selector rod that passes into the gearbox allows excess fluid (behind the actuator back plate) to go into the gearbox. So that is possibly where the fluid is going.
I think you said the wrong oil has been put into the Selespeed reservoir? Perhaps we have to assume the leak is the result of some seals have been damaged by having the wrong oil in there.
Therefore, I think it needs the actuator to be taken apart, cleaned of the oil residue, and seals need to be replaced to stop it leaking. I don't know which seals specifically, but there are certainly two small green O-rings behind the back plate that could be a good start.
Just my take on it...
'00 GTV V6, '08 FIAT 500, shell and parts for a '71 FIAT 850 Coupe