changing from low to high ratio on the move?

I tow a horse trailer with one or two horses weighing a max of 2500kg with my TD5 manual. Even on inclines I pull away OK in high ratio, but I have been told that starting inlow range is easier on the clutch and transmission.(makes sense)

So can I pull away in low range then switch to high (at low speed obviously) without damaging the transfer box? If this is possible/advisable, would double declutching help or is there another technique?

hi/lo is a simple dog clutch ,you may be able at times to judge it right but id start in high if possible,

Yes, double de-clutching.

Takes a bit of practice and you need to do it positively.....not try and 'ease' it in

It's all in the D2 owners handbook below is just a snippit of info.

Changing from LOW to HIGH on the move
With the vehicle travelling NO FASTER THAN
60 km/h (38 mph), depress the clutch and
select neutral in the main gearbox. Push the
transfer gear switch fully forwards to the ’HIGH’
position and release it (the switch returns to the
centre position when released).
While the range change is occurring, the LOW
range indicator at the switch stays lit and the
HIGH range indicator starts to flash. The LOW
range indicator in the instrument pack display
also starts to flash.
When the range change is complete, the HIGH
range indicator light at the switch illuminates
constantly, and the LOW range indicator lights
at the switch and on the instrument pack
display extinguish, a warning chime will sound,
and ’HIGH RANGE ENGAGED’ is displayed in
the message centre* for a few seconds.
After range change completion, depress the
clutch and reselect the most appropriate
manual gear for the vehicle speed. For example,
once HIGH range has been engaged, it may be
appropriate to select a lower manual gear to
keep the engine speed in a suitable rev range.

switch ,its a lever and dog clutch on all disco 2s ive seen ,no smooth way to try range change at any kind of speed

Discool that doesn't ring true? The hi low change is a gear lever not a switch on mine and the label says only change at up to 8kph / 5mph from memory? I doubt mine would do 38mph in low range anyway!!!!

There are no warning lights or displays either?

discool said:

it's all in the d2 owners handbook below is just a snippit of info.

changing from low to high on the move
with the vehicle travelling no faster than
60 km/h (38 mph), depress the clutch and
select neutral in the main gearbox. Push the
transfer gear switch fully forwards to the ’high’
position and release it (the switch returns to the
centre position when released).
While the range change is occurring, the low
range indicator at the switch stays lit and the
high range indicator starts to flash. The low
range indicator in the instrument pack display
also starts to flash.
When the range change is complete, the high
range indicator light at the switch illuminates
constantly, and the low range indicator lights
at the switch and on the instrument pack
display extinguish, a warning chime will sound,
and ’high range engaged’ is displayed in
the message centre* for a few seconds.
After range change completion, depress the
clutch and reselect the most appropriate
manual gear for the vehicle speed. For example,
once high range has been engaged, it may be
appropriate to select a lower manual gear to
keep the engine speed in a suitable rev range.

Click to expand...

bang !

m500dpp said:

I tow a horse trailer with one or two horses weighing a max of 2500kg with my TD5 manual. Even on inclines I pull away OK in high ratio, but I have been told that starting inlow range is easier on the clutch and transmission.(makes sense)

So can I pull away in low range then switch to high (at low speed obviously) without damaging the transfer box? If this is possible/advisable, would double declutching help or is there another technique?

Click to expand...

Why bother?? If you can set off with ease in high box why mess about, you'll most likely do more harm than good. It's daft advice you've been given, forget it.

Why bother?? If you can set off with ease in high box why mess about, you'll most likely do more harm than good. It's daft advice you've been given, forget it.

Click to expand...

Yes that is what I am doing now, just occassionally the exit from a horse show is a steep incline where low would be better to start of. My "reserve" strategy would be to use low to pull away and get onto the level then stop and get into high. Not needed it yet.........

I was to hasty that info was for a RRS which I copied for a mate.

Now for a D2.

Advanced method (Manual gearbox vehicles)
Changing from high to low on the move:
With the vehicle slowing to a stop and travelling
NO FASTER THAN 5 mph (8 km/h), depress the
clutch and push the transfer lever into neutral.
Just before the road wheels stop turning (and
with the clutch still depressed) push the lever
fully forward into ‘L’ (low).
NOTE: Use positive and confident moves, but
do not rush the gear change.
Changing from low to high on the move:
Changing from ‘L’ (low) to ‘H’ (high) can be
achieved without stopping the vehicle, as
follows:
1. Apply slight backward pressure to the
transfer gear lever in preparation for
changing.
2. Then, in three simultaneous moves,
depress the clutch, release the accelerator
and pull the transfer lever into neutral.
3. Release the clutch pedal for approximately
3 seconds before depressing it again and
moving the transfer lever firmly into the
high position.
4. Finally, select a suitable main gear, release
the clutch and continue driving in the
normal way.

m500dpp said:

Yes that is what I am doing now, just occassionally the exit from a horse show is a steep incline where low would be better to start of. My "reserve" strategy would be to use low to pull away and get onto the level then stop and get into high. Not needed it yet.........

Click to expand...

reserve strategy seems best as the dog teeth in t/box wont like there edges knocking off

Also.. from the handbook.

LOW range should ONLY be used in situations
where low speed manoeuvring is necessary,
such as reversing a trailer or negotiating a
boulder-strewn river bed, or when moving off
while heavily loaded or towing. On vehicles with
manual transmission, this will prevent
prolonged slipping of the clutch.
Also use LOW range for more extreme off-road
conditions, such as steep ascents and
descents. DO NOT attempt to use the LOW
range for normal road driving.

Just use low box (will take you to 30mph) then when you get on flat, stop and stick it in high

m500dpp said:

Yes that is what I am doing now, just occassionally the exit from a horse show is a steep incline where low would be better to start of. My "reserve" strategy would be to use low to pull away and get onto the level then stop and get into high. Not needed it yet.........

Click to expand...

That's how it should be done, I often use low box to maneuver my caravan as it saves a lot of clutch slipping.

There is nothing wrong with changing from low to high.

From fifth low at about max 25mph, depress clutch, pull lever out of low range. Lift off clutch, let revs drop a bit, then depress clutch again and engage high range preferably engage high third gear depending on road speed.

As has been said, takes practice but for a TD5 you shouldn't need to do it.

I have done this when towing heavy trailers at work, only ever use it for pulling away though, first gear, then once moving a quick shift into hi range and away we go. I wouldn't want to do it at any higher speeds than crawling and any higher up than 1st or 2nd low. But I'm no expert so you may be able to.

you can change to hi on the move but if done often you will wear the dog teeth prematurely

Why the post office insisted on using Eaton twin split gearbox fitted lorries amazed me, I could never get used to them and was forever crunching the gears. So this is a doddle.

Well.

It is completely possible at any speed as long as you can match hear speeds.

I find that if I floor it in low 5th I am doing around 20 mph or so.

I then press clutch and release accelerator, transfer neutral, main 4th, slight throttle and slot into transfer high.

No dramas or crunches at 20mph, because I worked out that low revs high 4th gives same speed as high revs low 5th, so it slots right in.

Can even do it real quick by using my elbow to change the main box and hand on transfer box.

Go me

jamesmartin said:

switch ,its a lever and dog clutch on all disco 2s ive seen ,no smooth way to try range change at any kind of speed

Click to expand...

Any friend of mine, who was involved in transport, which included the driving of many trucks for testing and training purposes used to regularly drive his disco like this when towing heavy loads.

The difference was the half century of experience driving many vehicles and many of which were crash gear boxes.