Selespeed uses 2 different oils to operate the gear box.
1. the main g/box uses 75w/90, 2 litres of it, filled via a 'bung' at the front of the g/box, drain is down near the sub-frame, passengers side.
2. the selespeed gear selection system uses either Tutela CS [ or Castrol Dextron III ], it reservoir & pump is located under the passenegrs wing near the battery.
Often people think thats the windscreen washer bottle so please DO not put water into this reservoir.
this is a closed loop system which should rarely if ever need 'topping up', the whole system hold 600cc/ml
what age is your car?
if you are statioaray, with the engine OFF can you select all 5 forward gears + reverse?
to monitor this system you need:
a. a laptop
b. an interface cable, which i can sell to you [ PM me if youo are interested ]
c. software form AlfaDiag Alfa Romeo Diagnostic Software
[ €60 ]
there is a 'Sticky@ thread at the start of each page referring to selespeed issue, might take a while to read all the pages but the 1st post links to a website with load sof good selespeed info.