Often it is a problem to get the torque converter properly installed.
There is a instruction here on European Transmissions
Europeantransmissions and parts Inc.
direct link

Important Torque Converter Installation Tips

copied from above link:
Important Torque Converter Installation Tips

1.PREPARE THE CRANKSHAFT AND TORQUE CONVERTER FOR INSTALLATION

a)always check crankshaft for burrs and out of round
b)remove rust with emery and lightly grease pocket
c)remove paint ffrom conveter crank pilot with emery
d)pour one quart of ATF into the converter
e)check the flex plate for cracks and worn teeth
f)install the converter on front of the transmission

2. CHECK CONVERTER TO FLEX PLATE ALIGNMENT

a)after bell housing bolts are tight, the check free movement of converter. It should have 1/16 to 1/8" of clearance between pads on converter and flex plate. If you have more than 1/16 to 1/8", install equal thickness washers to reduce clearance to 1/16 to 1/8". If not enough clearance, remove transmission and check to see if converter is seated in front pump properly.
b)draw converter bolts up evenly so as not to pull converter into a bind causing vibration and pump bushing failure.
c)if vibration occurs after installation, mark converter to flex plate and rotate the converter one bolt hole at a time.

3) the number one cause of vibration is failure to prepare crankshaft for installation. Each time the converter is installed without sanding out the crankshaft rust, removing the paint from converter pilot and adding a little grease the converter may be drawn up crooked with the first bolt, causing the converter to run- out and usually ruining the pump bushing.
The 2nd most common complaint on converters is a whine after installation. This usually means too much clearance between converter pads and flex plate. This draws the converter hub too far out of the pump drive gear causing the gear to rock.


Then I found on the Landrover Forum this information:

When re-fitting the ZF autobox it is essential that the torque converter is sitting at the correct depth relative to the face of the bell housing before the engine is bolted back on to the bell housing. If it is not set at the correct depth it is a 99% certainty that when the bolts are tightened the gearbox oil pump will get smashed.

The depth is determined from the serial number of the gearbox:

The box code is the last 3 digits of the second number down on the name plate on the left hand side of the autobox.

Box Code.....................Depth in mm

061.................................. 22

064....................................22

065....................................27

332....................................51

593....................................51

699....................................51

727....................................27

728....................................83

740....................................51

741....................................51

742....................................51

744....................................18

748....................................18

747....................................27

757....................................27

759....................................27

763....................................83

764....................................27

765....................................27

766....................................96

767....................................27

768....................................83

769....................................83

The measurement is made as shown in the following diagram:


http://i962.photobucket.com/albums/a.../TCFitting.jpg

Land Rover Owner • View topic - ZF4HP22 Auto Box Re-Fitting