Have a 1996 RR4.6HSE with faultcode P1777,gearbox ignition retard request line fault.Switching on the key,the sport modelight on the H-gate lights up.After starting the engine,the lightgoes out after 30 seconds and a message "gearbox fault"comes on the display.Gearbox bangs when changing gear.Help needed please.Changed the Gems ECU,gearbox ECU,position switch and vehicle speed sensor.Fault still there.
Regards
Marius.[&o]

 

Get it into a shop so they can scan your system to see what is causing the fault to show up.
I wouldn't drive it till you can get it in some where, might even try a tranny shop.