When it comes to transmission oil, Lotus has only the following recommendations: use Castrol TAF-X 75W/90 (Lotus part number A082F6552S). If the car is operated in continuously very low ambient temperatures, you can use Mobil SHC 75W/90. However, if you talk to members of the Esprit community, they unanimously recommend that you use Redline MT-90. Many owners claims that it feels that it feels like they have a new transmission and that the shifts are a lot smoother when they use this oil.
By the way, the transmission oil capacity is 3.2 US qt (3.0 litre).