Swapping a 3.9 from manual to auto

[Lumbering Jack]

Hi guys,

This may have been covered before but I can't get the search to work at the mo - how big a job is it toi swap a 3.9 over from manual to auto?  Is it just a case of taking one box and the clucth out and fitting the torque converter, auto box, oil cooler ,kick down cable, shifter etc off an auto or is it much more complex?

Also would the box etc have to come off a Disco or could it be a RRC one and is there any difference between 3.5 and 3.9 fittings?

Mine's about due a box and I can't help thinking auto would be nice.

[Range Rover Blues]

I've been planning to do mine for years, so let's see.

Engine is esentially the same, unbolt the flywheel, fit the adapter, flexplate etc.  You need to remove the spigot bearing.

Gearbox bolts up to the same place,
Transfer box the same,but the bracket might be differnet on top of the gearbox :-k

The rubber sheet that fills the tunnel is differnet as is the top of the console.  The sifter bolts to the tunnel too.

Pedalbox is different (brake pedal is wider).

Kicksodw as you say, though the brackets are already there

There are 2 oil coolers. one ahead of the rad, the other in the LHS end tank or the main rad.

You need to wire up the starter inhibiter, reverse switch and gear selector switch, the later tell s the engine ECU what gear the car is in.  On a manual this switch is replaced by a resistor but on an auto it makes the ECU raise the idle speed slightly when you select a gear.
he same, crossmember is the same IIRC, gearbox mounts the same.


Oh, and you need a new badge on the boot :lol: