how does a diff actually work?

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
S

stushine

New Member
Posts
46
as above, was out in a mates defender today, climbing up a rocky steep hill, he used diff lock a few times for some large rocks, and the diff light came on, he took diff lock off and went backwards and forwards a few times, did a bit of a wheel spin and the light went out.

now what i dont understand is what causes the light to come on? i was told it was something to do with winding the diff up to much or something?

any 1 got a nice simple way to explain how a diff works and what to do in this situation etc?
 
the light comes on when diff lock is engaged. so the times the light wasnt on then your difflock wont have been engaged.

by the way the difflock doesnt actually lock the axles diffs it locks the centre diff so if u are well and truely stuck without diff lock engaged then you will have ONE wheel spinning out of four, if you are stuck with it engaged then you will have TWO spinning, one on the rear axle and one on the front axle.
 
so what would cause a rear diff to explode?
how do you know how far you can push the diffs when locked?
 
Running it round corners with diff lock engaged (especially on tarmac) would probably cause a diff a fair bit of damage , especially if you had axle lockers. Im not sure exactly what damage it would do though, could snap a half shaft, prop shaft...duno really.
 
To put it simply there are your two prop shafts connected to your transfer case, now with the diff lock in the normal unengaged position those two props are in essence separated, with the driving power going to both but allowed to turn at different velocities - a differential. When you engage the centre diff you slide a locking system into the diff so now it’s locked together like one solid prop shaft from the front diff to the rear diff and they have to turn at the same speed.

When you disengage it sometimes you have a force on the two parts of the diff because the front and rear axles have "wound up" and this force will keep the diff locked until the force can be removed: backing up, jacking up a wheel (it will then spin off the windup) etc... This force can get to be quite a lot and can rip parts of the drive train apart because the back and front axle is being forced to run at the same speed, on gravel if you turn hard lock with diff lock on you will hear a wheel or two skidding because they are being forced to turn further than they need, however on concrete or tarmac it can lead to snapped half shafts, diffs being torn apart, UJ's being damaged - whatever the weakest part at the time is really.
 
so how do you actually know when its wound up??


a mate of mine blew a hole in his rear diff housing and destroyed the diff climbing up a rocky hill. what would cause this? would it be cause it was wound up?
 
Have a look here. Howstuffworks "What is a Differential?" there is a better one but can't find it now, do a search I posted the link a bit back.

Any how wind up is likely to occur when the centre diff has been locked and the front propshaft has been forced to turn at a different speed to the rear propshaft cos the wheels are turning at different speeds like going round a bend, and all the play has been taken up in the drive train causing either prop to force either axle diff to turn at a different speed to the wheels causing whatever is the weakest part in the drive train to bust, or a wheel to spin.
 
stushine said:
so how do you actually know when its wound up??


a mate of mine blew a hole in his rear diff housing and destroyed the diff climbing up a rocky hill. what would cause this? would it be cause it was wound up?
Click to expand...
Too much right foot
 
always try and use it only when you need it, pain in the arse when on a mixed terriain, especialy when yer mates have autos and only have to use H-L it kinda leaves yer behind sometimes but better safe than sorry.
 
stushine said:
so how do you actually know when its wound up??


a mate of mine blew a hole in his rear diff housing and destroyed the diff climbing up a rocky hill. what would cause this? would it be cause it was wound up?
Click to expand...


The light will usually stay on, because although the shifter is back where it should be the locking mechanism is still locked, the switch is on the system, not the shifter. Once the windup is removed, it will unlock because its not being held there by the shifter and the light will go out.
 
The light will iluminate (come on) when electricity is passed through it!
It matters not whether the switch is engaged if there is no electricity
 
peeps need to start searching for these posts or threads as they come up once to often now. newbies should have to read and take a quiz at the end of it on this before they can actively use the forum :rolleyes:
 
chris_mack said:
the light comes on when diff lock is engaged. so the times the light wasnt on then your difflock wont have been engaged.

by the way the difflock doesnt actually lock the axles diffs it locks the centre diff so if u are well and truely stuck without diff lock engaged then you will have ONE wheel spinning out of four, if you are stuck with it engaged then you will have TWO spinning, one on the rear axle and one on the front axle.
Click to expand...


but if you get difflockers all 4 can spin
 
You must log in or register to reply here.

Similar threads

C
Defender TDCi Puma 90 - Diff Lock Light
Replies
12
Views
586
crashmat
C
N
Rear diff issues
Replies
5
Views
770
niko-h
N
F
Landrover 90 Diff problem?
Replies
10
Views
1K
Anaconda
A
9
300TDI Doughnut
Replies
9
Views
792
9255 steve
9
R
63 reg Disco TDV6 268bhp auto commercial, battery light on
Replies
9
Views
286
roythebus
R
Back
Top