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.

A common fault on the early R380 gearboxes was the 4th gear baulk ring. The slot locating the synchro slipper wears and allows the baulk ring to rotate too far. This blocks the synchro assembly. It will be necessary to rebuild the gearbox, and replacing the baulk ring with a later type will eliminate this fault.

The most common cause is worn mainshaft spline but other things to check the A frame ball joint and the halfshaft drive flanges, especially if you have a 300 tdi Defender. To check mainshaft spline wear remove the PTO cover and with the main box in first gear rock the car backwards and forwards whilst looking into the end of the input gear. If the spline is worn you will see movement of the shaft in relation to the gear. Replace the gearbox and transfer box input gear (use a cross drilled gear to prevent recurrence of the problem).

There are three possible problems. 1) The mainshaft spline has worn away and is not engaging in the transfer case input gear, (most common) 2) the centre has torn out the clutch friction plate or 3) the mainshaft has sheared just inside the rear of the gearbox. 1) and 3) will require a rebuilt unit.

The layshaft extension has sheared off effectively disconnecting these two gears. You require a rebuilt or new gearbox.

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 MTF94 in your R380 box.

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.

This is the chain in the transfer case jumping over the sprockets, needs a rebuild or at least a new chain.

First of all check you have lost both forward and reverse. If this is the case (if not see end of paragraph) it could be that the output shaft or viscous coupling splines have stripped. To check remove front propshaft or lift a front wheel and try rotating the front output flange with your mainbox in "park", if you have an automatic, or 1st gear if you have a manual, and the handbrake applied. If the viscous coupling spline has gone the flange will rotate easily. If the mainshaft spline has failed the effect will be similar but you will hear some sound as the centre differential rotates around the damaged spline. The transfer box will need a full rebuild. If you have an auto and have just lost forward it will be the A clutch in the autobox and the autobox will need a rebuild.

This is only available on a suffix C or later (last number of transfer case), it cannot be changed on Suffix A or B transfer boxes. On a 1.667 or a 1.410 removal of the gear is simple, it just slides out; on a 1.222 it in necessary to rotate the intermediate gear to a position where the teeth on the middle and rear gears are in line and allow the input gear to slide through. It is not possible to change a 1.003 in situ.

Some "pattern" gears are not "crowned" during manufacture and will whine because of the edge contact this creates

Sometimes the difflock indicator switch sticks and this prevents the difflock selector mechanism moving across. Back off the switch one turn and try difflock again.

Check that the bolts you used to bolt the transfer box to the main box are in the correct positions. It is possible to fit a "longer" bolt in a position which will jam the intermediate gear and prevent it rotating. There are three bolts down each side attaching the transfer box to the main box and it is the middle of the three on the right hand side that causes the problem. On earlier transfer boxes a "stud" was fitted in this position to reduce the possibility of error. Sometimes the stud is omitted on later boxes or rebuilds.

We recommend you use ATF Dextron 2/3 in your Borg Warner transfer box?

If your vehicle is pre 1989 you have the LT230 and I would suggest it is stuck in difflock. If your vehicle is after 1989, Classic or New Shape, then you have the Borg Warner transfer box. When the tyres scrub this indicates the Viscous Coupling unit within the transfer box has seized and needs replacing. We can supply either rebuilt transfer boxes or replacement Viscous Coupling units on their own. Be warned, neglecting this problem causes immense strain on the drive train, which often results in failure of CV joints and/or differentials, as well as rapid tyre wear. For information on fitting a coupling please visit our website and for prices please see below

The most common error when setting the difflock is not understanding which position to set the input shaft to. As you noticed there are three positions on the difflock input shaft; counterclockwise, centre and clockwise. The counterclockwise position is a "dummy" i.e. not used. You need to set the linkage up to move from centre position to clockwise position. If you set this up to this position you should resolve your problem.

We make a “High Ratio Transfer Case Kit”. This has the effect of permanently raising high range by 32% and leaves low range ratio unchanged. This is as strong and quiet as the original, cost effective and can be used with the PTO. It does not necessitate the re-calibration of the Speedo. We are only able to supply this in kit form.

The later P38"s and the Disco II don"t have dipsticks on the autobox, instead on the front face of the sump they have a filler level plug, The fill proceedure is first to put the transfer case in neutral so theres no load, fill with oil until the oil overflows, autobox in N, start the engine, it will suck all the oil up so you need to pump like crazy to top it back up until it overflows again, put the transfer case in high and move the shifter up and down the gate a few times, a few seconds in each position, check level, the engine revs should now drop when you shift from N to D as it takes up load, plug in, test drive, check level, engine running in N.

there is a good guide to oil temps here

One of the one way clutchs has failed which causes the loss of drive in D, it will sometimes pull off in 3rd as the ECU recognises a fault and puts it in 3rd which is "limp home mode", It needs a rebuild.

Your A clutch (forward drive) has failed and you will require a replacment autobox.

Check the setting of the kick down cable, if it is too tight the gearbox will think you have more throttle applied than is the case. Check and adjust the gearbox accordingly. As a guide the looser the cable, the earlier it will shift, visa versa the tighter the cable, the later it will shift.

It sounds like the torque converter sprag clutch is slipping. Two common symptoms are 1) as you describe sluggish pulling away; sprag clutch is slipping which effectively means no torque multiplication; and 2) the sprag clutch has seized. In this case the car pulls away fine but at 2,000-RPM ish it feels like the brakes are jammed on. Solution – replace the Torque Converter.

We recommend you use AFT Dextron 2/3.

The first thing to do is to remove the oil cooler pipe from the bottom of the gearbox (put a container under the open end to catch the oil) and start the engine. You should get a good flow of oil. If not the pump has been broken during installation and will need replacing/rebuilding. The torque convertor must be fitted to the gearbox, located correctly on the pump and locked into postion before the gearbox is offered to the engine, otherwise damage will occur to the pump, resulting in no oil flow and subsequent to other parts of the autobox.

It sounds like you need to change the filter! In the cold weather, i.e when the oil is cold and more viscous, if the filter is partially blocked it will take some time for the pump to draw oil through it. Once the oil becomes warm it flows more freely and can pass through the filter more easily. Hence the problem only occurs when the oil is cold. To remedy this problem your filter needs to be changed. This should be done sooner rather later to reduce the possibility of damage to the autobox, by the clutches “slipping” during this slow engagement.

It sounds like you need to change the filter! In the cold weather, i.e when the oil is cold and more viscous, if the filter is partially blocked it will take some time for the pump to draw oil through it. Once the oil becomes warm it flows more freely and can pass through the filter more easily. Hence the problem only occurs when the oil is cold. To remedy this problem your filter needs to be changed. This should be done sooner rather later to reduce the possibility of damage to the autobox, by the clutches “slipping” during this slow engagement.

A sprag clutch has "inverted" and will need replacing. No further damage will occur if you continue to drive but you will need to select "1" every time to start moving. A rebuild is required to correct this.

The governor valve is sticking, which can be caused by contamination. i.e. clutch plates or other parts disintegrating. The fine debris finds its way past the filter and tends to accumulate in the governor, causing it to stick. A temporary solution is to remove and clean the governor. The problem will often recur as debris from damaged parts continues to build up in the governor. If the problem continues after cleaning the governor then it may be necessary it replace your Autobox.

We have noticed many customers reporting this fault starting a few days after an oil and filter change and after researching this using our experience and the expertise of others in the trade we have come to the conclusion that as ATF oil is a detergent type oil, when the oil is changed this will dislodge and stir up settled debris in the autobox which in turn jams the governor valve. In light of this although it sounds controversial it is debateable if changing the oil and filter is a good idea, some say if the box it going to fail it will fail if the oil is good or bad and their advice is leave it alone. I am still undecided but the truth is I get a lot of calls from customers thinking they are looking after the autobox by servicing it and a few days later this fault occurs.

We can supply rebuilt exchange autoboxes and offer a sameday fitting service, with free use of a courtesy car. Please call for details.

What vehicle do you own?

a) Discovery - go to point 1

b) Defender 90/110 - go to point 2

c) Range Rover Classic - go to point 3

d) New Shape/P38 Range Rover - go to point 4

e) Series Land Rover - go to point 5

1)* *Discovery

*a)* Is this for the front, if yes see below, if for rear go to point (b)

Front – 10 spline  - you will need a truetrac, model code 416

Front - 24 spline – you will need a truetrac, model code 407

*b)* Is your vehicle 10 or 24 spline – if 24 spline go to point (c)

Rear - 10 spline - you will need either a truetrac, model code 400

Or a Detroit Locker, model code 174

*c)* Rear - 24 spline - you will need either a truetrac, model code 383

Or a Detroit Locker, model code 173

2)* *Defender 90/110

*a)* Is this for the front, if yes see below, if for rear go to point (b)

Front – 10 spline - you will need a truetrac, model code 416

Front - 24 spline – you will need a truetrac, model code 407

*b)* Is your vehicle a 90 or 110 – if 110 go to point (d)

Is your 90 vehicle 10 or 24 spline – if 24 spline go to point (c)

90 Rear - 10 spline - you will need either a Truetrac, model code 400 or a Detroit Locker, model code 174

*c)* 90 Rear - 24 spline - you will need either a Truetrac, model code 383 or a Detroit Locker, model code 173

*d)* Is your 110 vehicle non Td5 or Td5 – if TD5 go to point (e)

Non TD5 - you will need a Detroit Locker, model code 225SL-36, there is not a Truetrac available for the Salisbury axle

*e)* Your vehicle is a TD5.

- Salisbury axle – you will need a Detroit Locker model code 225SL-36 (no Truetrac available)

• Non Salisbury axle – you will need a Detroit Locker model code 173 and a P38 spacer

3)* *Classic Range Rover

*a)* Is this for the front? if yes see below, if for rear go to point (e)

*b)* If this 10 spline see below, if 24 spline go to (d)

*c)* If your 10 spline Range Rover is pre 1983 you will need a Detoit Truetrac model code 416 and a pair of imperial bearings sleeves

If your 10 spline Range Rover is post1983 you will need a Detroit Truetrac model code 416

*d)* Front – 24 spline - you will need a Detriot Truetrac, model code 407

*e)* If the Truetrac/Locker you require for the rear of your Range Rover is 10 spline see

(f), if 24 spline go to point (h)

*f)* If you require a Detroit Truetrac see below, if you require a Locker see (g)

If your vehicle is pre 1983 you will need a Detriot Truetrac model no. 400 plus a pair of imperial bearing sleeves

If you vehicle is post 1983 you will need a Detroit Truetrac model no. 400

*g)* If you require a Detroit Locker see below:-

If your vehicle is pre 1983 you will need a Detroit Locker model no. 174 plus a pair of imperial bearing sleeves

If you vehicle is post 1983 you will need a Detroit Locker model no. 174

*h)* If you have a 24 spline and require a Detroit Locker for the rear of your vehicle see below, if you require a Detroit Truetrac point (i)

You will need a Detroit Locker model no. 173

(i) You will need a Detroit Truetrac model no. 383

4)* *New Shape/P38 Range Rover

*a)* Is this for the front? if yes see below, if for rear go to point (b)

You will need a Detroit Truetrac 407 & a P38 spacer

*b)* If you require a Detroit Truetrac you will need model code 383 and a P38 spacer

If you require a Detroit Locker you will need model code 173 & a P38 spacer.

5)* *Series Landrover

If you have Series 1 (80 or 107) or Series II (88 or 109) go to (a), Series IIa go to (c), or Series III go to (f)

*a)* If your requirement is for the front of your Ser I or II vehicle see below, if you require a rear see (b)

You will need a Detroit Truetrac model no. 416 plus a 4.7 spacer ring and imperial bearing sleeves

*b)* If you require a Detroit Locker for the rear of your Ser I or II you will need model code 174 plus a 4.7 spacer ring and imperial bearing sleeves.

*c)* If you require a Truetrac for the front of your Ser 11A see below, if you require a Locker or Truetrac for the rear go to (d)

You will require a Detroit Truetrac model code 416 plus a 4.7 spacer and imperial bearing sleeves

*d)* If you have an 88” vehicle see below, if you have a 109” go to (e)

If you require a Detroit Truetrac you will need model code 400 plus a 4.7 spacer and imperial bearing sleeves

If you require a Detroit Locker you will need model code 174 plus a 4.7 spacer ring and imperial bearing sleeves

*e)* If you require a Detroit Locker for the 109” you will need model code 225SL-36.

The Detroit Truetrac is not available for this model.

*f)* If you require a Truetrac for the front of your Ser 3 see below, if you require a Locker or Truetrac for the rear go to (g)

You will require a Detroit Truetrac model code 416 plus a 4.7 spacer and imperial bearing sleeves

*g)* If you have an 88” vehicle see below, if you have a 109” go to (h)

If you require a Detroit Truetrac you will need model code 400 plus a 4.7 spacer and imperial bearing sleeves

If you require a Detroit Locker you will need model code 174 plus a 4.7 spacer ring and imperial bearing sleeves

*h)* If you require a Detroit Locker for the 109” you will need model code 225SL-36.

The Detroit Truetrac is not available for this model.

We recommend you use EP90 in your Detroit Truetrac.

We recommend you use EP90 in your Detroit Locker?

We recommend you use 75W90 SPECAPIGLS in your IRD unit.

To make the Freelander handle well the front wheels are driven faster than the rear wheels. To accommodate this difference a Viscous Coupling is fitted in line with the rear prop shaft, which constantly slips. On the earlier Freelander’s this ratio difference is to great causing the viscous coupling to be overworked and thus seize solid. Once seized the front wheels fight the back wheels causing transmission wind-up this rapidly accelerates the wear on the rear diff and the IRD unit, which will cause the imminent failure of either/both. Thus be warned if you need to change your diff or your IRD the viscous coupling must also be checked and renewed if necessary to stop the problem. Look at prices below for Freelander IRD, Viscous Coupling units, and fitting services.

You can contact us by reading the details on our contact page.