You have to look on the passanger side of the bell housing for a sticker. The labelled E30 transmissions used 17mm external wrenching oil plugs; bolts that you can put a socket on. The one non-labelled transmission used a internal wrench oil plug; bolts that you need a 17mm allen key for.
If you have a red sticker, then you need ATF. (BMW recommends Dexron III)
If you have a green sticker, then you need synthetic gear oil.
If you have no sticker, then you need any API-GL-4 SAE 80 Non-Hypoid gear oil (or single grade HD engine oil)
In terms of Redline, for the red sticker, use D4 ATF. For the green, use Redline MT90 and for no label use Redline MTL GL-4 70W-80.
Personally, I recommend Royal Purple whenever possible, but that's a personal preference. Syncromax is their Dexron III replacement for red label transmissions. I think their Max Gear Oil works for the green and non-labelled trans.
REMEMBER: Be safe and have fun is Rule Number 1.
Originally Posted by 411
just letting this furom [*forum] know