Diff lock and low & high range ratios

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fishsponge

fishsponge

New Member
Posts
1,432
Location
Cambridgeshire, UK
Hello,

A couple of things, if I may... Here are the positions I can put my diff lock lever into (as I'm sure you are all aware)!

1 2
. N
3 4

First of all, I assume I'm correct when I say engaging the diff lock simply locks the centre diff, thereby meaning that I will always have at least 1 wheel spinning on each axle. If, for example, i go sideways into a rut and bottom out, leaving both left wheels off the ground, I'm stuck, right? If, however, the front of the Landy goes into a rut, leaving both front wheels off the ground, the rear wheels (at least one of them) will still rotate regardless.

I understand the concept of wind-up already, so as long as my understanding of the diff lock is correct, I think I'm good to go!

So, now on to my understanding of the lever positions...

1 - Diff lock, low range
3 - Diff lock, high range
2 - No diff lock, low range
4 - No diff lock, high range

Hopefully that's correct too! :D

As for the procedure for using this lever, I understand that ideally one should stop completely, move the gear lever into neutral, move the diff lever to wherever, then put the gear lever back into gear or ("D" for autos) and pull away, right?

And finally... what is the ratio between high range and low range? i.e. at a given RPM, how fast will I be going in low range compared to high range?

Or is it much more complex than that?? I assume not, but ya never know! :D
 
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first of all decide what gear you need for the land ahead of you, do you need low gear, or low gear with the centre diff locked ? (mud, rocky steps when loss of traction will probably occure etc)
Slow the vehicle down to WALKING pace (you need the vehicle to be moving very slowly) slip the main gear-stick into neutral, then your high/low stick into the position you required, (either with or without lock) then go back into gear with the main gear-stick deciding which gear is required first, for example, 1st gear for downhill slopes, 3rd gear for uphill, 3rd or 2nd for rock steps uphill..
Use exactly the same procedure to change either out of locked to standard low range (don't use difflock when not required) or when going back up into high range.
you'll soon get used to what gear ratio's are like in low, but basically, 3rd low is similar to 1st high.
Don't try changing in a rush part way through something, you need to sort it out BEFORE you attempt anything.
 
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what gafferjim said but from what you have said i would be surprised if you need diff lock at all. Had a weekend at the Peaks and only used diff lock about 3 times all weekend.

Its always worth putting it into diff lock once or twice a month to keep it free (they have a tendency to seize if left unused).
 
Assuming yours is a manual gearbox:

you dont need to clutch to engage the difflock, you can simply slam it over left to engage center difflock if the ground looks tricky, then back over to the right when on better ground.

however shifting low-high, or high-low needs the clutch.

Dont be concerned if the difflock light dosent go out straight away, it will more likely go out on the next gear change or if it is really stubbourn you can reverse a few feet to get it to disengage. sometimes it just needs the load taken off the drive train to disengage.
 
ah... so engaging it at 70mph is pointless. unless you get really lucky for a moment, of course, but engaging it at 70mph will cause no damage? surely it will...

and I still don't know whether I can engage it while stationary or not...

the reason I ask about engaging it while stationary is that if you get stuck with one wheel spinning, is it then too late to engage diff lock to get yourself out of it on the basis that the wheels have to be both moving and at the same speed for it to be engaged?
 
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fishsponge said:
ah... so engaging it at 70mph is pointless. unless you get really lucky for a moment, of course, but engaging it at 70mph will cause no damage? surely it will...

and I still don't know whether I can engage it while stationary or not...

the reason I ask about engaging it while stationary is that if you get stuck with one wheel spinning, is it then too late to engage diff lock to get yourself out of it on the basis that the wheels have to be both moving and at the same speed for it to be engaged?
Click to expand...

when stationary is fine and technically you can engage at any speed without causing any damage. as it doesn't alter the speed of the wheels rotation in any way. only changing from lo to hi does that.
 
fishsponge said:
ah... so engaging it at 70mph is pointless. unless you get really lucky for a moment, of course, but engaging it at 70mph will cause no damage? surely it will...

and I still don't know whether I can engage it while stationary or not...

the reason I ask about engaging it while stationary is that if you get stuck with one wheel spinning, is it then too late to engage diff lock to get yourself out of it on the basis that the wheels have to be both moving and at the same speed for it to be engaged?
Click to expand...

not while stationary, well you can move the lever but it wont come on until you start moving...so if youre already unmovably stuck youre buggered.
read the track ahead before you get stuck and or walk it first if unsure...if it looks like you might get stuck engage it first...wont do any harm.
Too many people seem afraid to use it most of the time...

yes 70mph is pointless as off road you ll be doing 20 at most, but it is still true you can engage at any speed...
 
foss said:
not while stationary, well you can move the lever but it wont come on until you start moving...so if youre already unmovably stuck youre buggered.
read the track ahead before you get stuck and or walk it first if unsure...if it looks like you might get stuck engage it first...wont do any harm.
Too many people seem afraid to use it most of the time...

yes 70mph is pointless as off road you ll be doing 20 at most, but it is still true you can engage at any speed...
Click to expand...



That's funny because I've engaged difflock from stationary several times. woithout it failing to be engaged when I moved off.
 
if yer have a auto then stop to change from hi to low.get the diff lock n range right before ya need it.If yefr off road chances are diff lock low is what ya want
 
excellent - thanks, people!

I did a bit of greenlaning this weekend and engaged it before what to me looked like a rather large puddle. I probably didn't need it, but ya never know...

It's a bit stiff to engage at the moment and quite hard to feel whether the lever is in the right place or not... presumably the "stiffness" is due to a lack of grease (and probably a lack of use in the past) and the lack of knowing where the correct position is is due to lack of experience, right?
 
redhand said:
That's funny because I've engaged difflock from stationary several times. woithout it failing to be engaged when I moved off.
Click to expand...

okay...all the Landiesive had have had the need for you to move forward or backward for the light to come on / go off indicating engaged/disengaged...ive never had a landy where lock is engaged whilst not moving...

if all 4 wheels need to be moving at the same speed to engage then how exactly will it come on if youre not moving then???? :doh::doh:
 
foss said:
if i went outside now & engaged diff lock & jacked up one front wheel I bet me bottom dollar it would spin freely...but its raining so I int :D
Click to expand...

I'll bet on it too......CDL has nothing to do with wheel spinning... for that they've invented TC.
 
mine comes on and off while stationary most of the time.
if one corner jacked up with diff lock engaged, i'll get maybe quarter turn before the clunk as diff lock falls in and it locks up.
the splines on the shafts in the diff have to be line up for the collar to slide across.

wouldnt advise on trying to engage it while spinning one wheel, as it will try to connect a rotating shaft to a splined shaft......
(ie when your stuck, or cocked a wheel)

when moving forward, both shafts turn at reletvely the same speed, so no problem there.
 
foss said:
if i went outside now & engaged diff lock & jacked up one front wheel I bet me bottom dollar it would spin freely...but its raining so I int :D
Click to expand...

sierrafery said:
I'll bet on it too......CDL has nothing to do with wheel spinning... for that they've invented TC.
Click to expand...

did this recently while freeing up my diff lock (completely seized and needed lots of persuasion ;)) and with one wheel in the air the diff would lock without moving the wheels.

sometimes it does require slight movement for the light to come on but I tend to try and read the terrain and only use it when i think it is required and take it out as soon as i can.

fishsponge, if yours is an auto and quite stiff you can switch between hi/lo at standstill by going into neutral and moving the lever. If you dont think it has moved enough put your foot on the brake and gearbox into D, slightly release the brake then reapply and go back into park/neutral and see if the transfer lever moves any further forward. This still happens to me sometimes but my transfer box looked like it hadn't been used in 10yrs+.

I find the best/easiest method is where possible roll along at walking pace in neutral and move the lever into high/lo. Works every time for me :)
 
Basically you're moving a dog clutch across to into another one to lock 2 shafts so they both turn together. If you're lucky and your dog clutches have stopped in line, or they're somewhat rounded off through use, then you've more chance of selecting whilst stopped, but you should have them slowly turning so they can slot in as the dogs pass each other. doing this at any speed will sooner or later smash them.
 
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