When you let go of the gearstick on either the LT77 or the R 380 Discovery boxes the stick will spring to the 3 / 4th gate. This gate position is set by the position of the plate shown here. This gate position must be adjusted correctly to agree with the selectors in the gearbox to ensure a good gearshift. When we rebuild the boxes we set this position but sometimes it needs fine tuning when in the car.

If the shifts to 3rd and 4th are not clean you may want to adjust this plate, to do this first you must drive the vehicle but when shifting into 3 and 4 instead of letting the gearstick go where it wants to go try holding it a little to the left then a little to the right, one way or the other it will drop in nicer. When you have worked this out you can slacken the 4 screws holding the plate and move the plate left or right accordingly to improve the shifts.

The best way of ascertaining the degree of wear is to chock the two front wheels, handbrake off, mainbox in first and jack up a rear wheel. Remove the PTO cover to the left of the handbrake and you will be able to see the gearbox mainshaft in the centre and the transfer case input gear around it. By rocking the handbrake drum you will be able to rock the gear around the shaft thus getting some idea of wear / backlash between the two.

Most rebuilt gearboxes, including ours, come without the "turret". This the part that the gearstick bolts to. If you pull back the rubber boot on the turret you will reveal two large springs and two adjuster screws and locknuts. The role of these springs and screws is to set the rest position of the gearstick when you let go of it and is referred to as the 3/4 bias setting. When you fit a new gearbox this can sometimes need adjusting to agree with the selector shafts to ensure a clean gearshift. Firstly you need to work out which way to adjust it, to do this drive the vehicle but when shifting into 3 and 4 in stead of letting the gearstick go where it wants to go try holding it a little to the left then a little to the right, one way or the other it will drop in nicer. When you have worked this out you can adjust the screws the springs are resting on to lean the stick left or right until it shifts better.

A common fault with these boxes is a thrust washer in the 1 - 2 synchro assembly splitting in half and blocking movement. Rebuild the gearbox and replace both thrust washers in the 1 - 2 assembly.

We recommend ATF Dextron 2 or 3.

This is very common on both the 200 and the 300 TDi engined vehicles. The clutch friction plate has a ring of springs, which are there to soften the knock of the diesel engine to stop it being transmitted to the driveline. Often especially with a new clutch these springs are quite tight and a lot of the engine knock goes through to the gearbox and makes the gears "chatter" together when the box is in neutral and the clutch up, it goes when the clutch is depressed. This can sound quite bad and does vary from car to car but is not detrimental to the life of the gearbox and we view it as an undesirable characteristic of the LT 77 and R 380 as opposed to a fault with either the gearbox or the clutch.

Inside the aluminium top cover of the gearbox, which is secured by two large Phillips head screws, you will find two large springs which rest on a L shape steel plate which give your 3th bias gate position. This L shaped plate is very prone to cracking off where it is bent which will result in you losing the 3th rest position when in neutral and thus the shifts will become vague. This plate is inexpensive and can be changed with gearbox in situ.The part number of this Bias plate is FRC9340.

Inside the aluminium top cover of the gearbox, which is secured by two large Phillips head screws, you will find two large springs which rest against an L shaped steel plate giving 3rdth bias gate position. This L shaped plate is very prone to cracking off where it is bent which will result in you losing the 3rdth rest position when in neutral and thus the shifts will become vague. This plate is inexpensive and can be changed in situ.