I'm confused about diffs and locks!!

[Strider01]

OK, now I've got a feel for the forum, it is time to baffle you all with my stupidity!! ;D

I have a 2002 Pathfinder.

Firstly, I THINK it is a part time 4WD because I can invoke 4WD through a dial on the dash 2WD - AUTO - 4WD HI - 4WD LO). Am I right in my terminology here?

Next (told you I'm new here!!), why do people fit diff locks when I thought when you engage 4WD on my Pathfinder the little yellow light comes on the dash to say the centre diff is locked. Why do you need to also fit diff locks to either front, rear or both axles? I know it is to increase traction but I always thought when you lock hubs or whatever you need to do on your particular car then they are locked.

I know there is more to ask but I'll start with these things first.

Thanks all
Strider01

[baby_troupe]

Most 4wds, whether part time or full time, when in 4wd provide drive to the front axle & also the rear axle.
Both of these axles, have a differential, to allow one wheel to spin faster than the other wheel, so you can go around corners, & in an open dif (which most 4wds have), really will only be driving one wheel.
When you lift 1 wheel off the ground, that whole axle will effectively be no longer providing drive, & if a wheel from the other axle is struggling for grip, you will quickly lose momentum & will soon stop with 1 wheel on each axle spinning, meaning that a standard 4WD is really only getting drive to 2 wheels.
If you have a limited slip dif (usually rear), what will happen is that the wheel which is slipping will not get all the drive on that axle, & some will be given to other wheel, which can often get you out.
What a dif lock does is to "lock" the dif, making both wheels on that axle spin at the same speed & if 1 is not getting grip, the other wheel will still provide drive.
With dif locks on both front & rear, you have all 4 wheels driving.

[BigBugga]

one of the last few issues did a full break down on diff locks and part time 4wd.
just cant find my copy


Think my son has borrowed it.

[Strider01]

Thanks for the info guys - baby_troupe pretty well explained it I think. Seems strange to be a 4WD and even when it is selected for 4WD (Hi / Lo) you can still only have 2 wheels driving the car. Almost feel ripped off actually! ;)

Ah well, looks like some locks are on the shopping list now!! Any suggestions for my Pathfinder guys?

Strider01

[baby_troupe]

Has your Pathy got LSD rear?
If so, I wouldn't worry about lockers until you have some experience.
When you go to the club meet this week, try to book in for Basic Driver Awareness with Wayne.
You will learn a lot about what your vehicle is capable of & you will really surprise yourself.
It is better to learn to walk b4 you try to run.

[BigDave]

concerning the light on your dash...

Cause your pathy is full time four wheel drive, you have a third diff - the extra being in the middle of the tailshaft, in that it has to slip on the road as the torque build up inbetween the front and rear wheels with both of them driving.

You need to lock this diff for four wheek drive to be effective. It is effectively the same as being in 4wd in a part time rig.

Dave

[Strider01]

Hi guys,

Thanks for the info. BT the Pathy has rear LSD pretty sure - I need to check the specs but I'm pretty sure on this. Hopefully catch up tonight.

BigDave, thanks also - still learnin' this stuff.

Strider01

[baby_troupe]

Strider,
Where were u mate, I had my eye out, but didn't see you.

[RobertM]

Doh!!

I forgot the meeting was on last night

[Strider01]

Hey baby_troupe,

I was there up near the front of the room. The only problem is I don't know who you are so I couldn't find you by looking out for a name tag!! I would have also felt fairly silly walking around asking everyone if they were baby_troupe ::)

Strider01

[Simon]

wow

[baby_troupe]

I was up near the back door, but was wlking around just b4 the start of the meeting hanging CDs with pictures from some recent trips on them to people who had requested them.
Oh Well, I guess I will catch you at one of the other meetings or the GPS day.

[308LUX]

A good webite: www.Howstuffworks.com
try the 4wheelin section

[Lug]

I seriously thought about diff lock on my rig and would love to get it but the front alone would cost 2k fully fitted with compressor for an ARB air locker.
I have a winch anyway so the need for it was pretty low for the type of places I'm going.
I ended up buying a set of chains to put on in the off chance I was ever going anywhere that was seriously tough driving, they're cheaper and will actually get you further.
Just gotta be careful not to rip up the track with em but that's another story...... :)

[baby_troupe]

Unfortunately Lug, the chains will stop at about the same point as good rubber, althought there are slightly better in soft terrain eg mud or snow.
Once you have 1 wheel up front in the air & 1 at the back not getting grip for whatever reason, even the chains are no good then. Only a locked dif will continue to provide drive to one of the other wheels to help propel you in the desired direction.
I personally have open difs at the moment & was planning to get one of them locked, but i have changed my mind, as I think I can get myself in enough trouble without them, so a winch is probably a better option for me for the near future.

[Strider01]

Hi Baby_troupe,

I must have arrived last meeting a couple of minutes too late - I didn't see you. Booked in with Wayne though for the Driver Awareness as you suggested.

Should be a great time with a lot to learn!!

When it gets nearer the next meeting I'll organise something with you so I can actually find you next time!!

Cheers
Craig

[baby_troupe]

No Worries Strider.

[Richo]

At the risk of sounding like a bit of a chest beating moron...

I reckon Roothy summed it up in a past issue when building up the mighty LWB green troopy...

without the front and rear difflocks you've really only got a 2 wheel drive ;)

LSD are fine until they wear out, but I still prefer manual locking hubs and driver operated cross axle locking diffs.

And although I know there is no substitute for good articulation (a wheel on the ground is a wheel that can help) but for many of the newer generation vehicles that still have rugged ladder chassis designs etc and IFS, diff locks and driver experience can overcome a hell of a lot of obstacles...and you still get a nice smooth drive home too ha ha!

Although a change in rubber can make an enormous difference...I've only just worn out the original Dunlop Supergrippers on my hilux and have rplaced them with Mud Terrain BFGoodrichs and I'm climbing hills with ease that I slipped around on before.

Thanks for your patience with me,
Richo

[Cozza]

I posed a similar question to the mag just last week and Ben gave me quite a good explanation of diff locks, LSD's, etc. If you want I can email to you, it is a bit long to post.

Basically, he suggested, if you have an LSD rear, leave there for now and put a manually operated locker on the front. LSD's still give you good drivability. I hope I have interpretted Bens email correctly.