1998 Super Custom G Living Saloon EX 'O/D Off' flashing

Hi,
Just since yesterday my car has been sluggish on take off and now the 'O/D off' light has started flashing on dash while driving.
Any ideas?? Thought maybe transmission, oil level seems fine.

It is an engine fault indicator, maybe not to do with the transmission.
You need to count the flashes and check against fault codes or get it hooked up to a dianostic computer.