Outer Limits 4x4 Board

Hey guys need some advice.
My mech dropped in a complete Discovery 3.9 V8 (1996) with the transmission and transfer case into my old 1989 Range Rover.

Now i've got a problem with engaging low range. It seems that after abit of searching there is some sort of lock out mechcanism. So how do i go about rectifying it? Any solutions or does anyone know how to get rid of it? Or dont tell me i need to drop the fecking gearbox to bin the solenoid? Can someone give me a brief through so that i know what i can tell to the mechanic?

Also another small problem is does anyone know how to rectify my fuel guage? Coz now i'm using the meters from the Disco and the fuel guage is under reading. Hence it shows i have an empty tank when probably i might have 1/3rd of fuel. So any suggestions how to rectify this problem.

Any advice is greatly appreciated.
Thanks in advance
Best Regards
Vic from Malaysia

what is the transfer case serial number ?

if it starts 40D, this is USA / Japan spec in which case you have the shift interlock which stops you cnahging from hi to lo unless in Park or Neutral, if this is the case you need to remove the 4 small bolts holding the 40mm round solenoid, remove the cover and solenoid, bin the solenoid and silicon the cover back on, done,

Yeah the halfcut is from Japan.
Pardon me asking this silly question but where is the solenoid?
So it's very straight forward by just taking it out. Bin it and silicon the gaps?

email me and I will send a photo,