Transmission fluid

Have 86 Fiero 2.5 with standard transmission. I just replaced the clutch. I lost some fluid of course and was wondering where to add? I don't see a fill nor drain plug. Was thinking I might just remove the speed sensor but would not know how much to add.

Thanks

4 and 5 speed isuzi tranny's you'll pull the speed sensor and there will be markings on it.