Diff locks front or back

Submitted: Tuesday, Mar 18, 2003 at 22:34
ThreadID: 3920 Views:1680 Replies:6 FollowUps:0
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What would be the advantages and disadvantages to installing a air locker to either the front or back. I have a Prado diesel (full time 4wd) with a slippery diff in the back. I was thinking the front to take full advantage of the lsd in the back. Is the reduced steering control a serious problem?

thanks in advance
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Reply By: Member - Chris - Wednesday, Mar 19, 2003 at 12:53

Wednesday, Mar 19, 2003 at 12:53
Hardy, I asked an ARB sales bloke the same question a year ago and he swore black & blue that if you're getting one to put it in the rear. He mentioned something to do with the common laws of physics?
A comment he made was:
The vehicle's rear wheels tend to push the vehicle up a slope whereas the front ones are pulling it up the slope ie. on a slope the front wheels aren't as effective and this comes into it as well... If you're fully laden or even empty when traversing a slope gravity will force more of the vehicles weight to the rear wheels giving more grip to the surface compared to the front ones.
I guess the second point would apply on level ground as well. I know with mine fully laden it's definitely heavier in the rear hence giving the rear tyres more 'bite' into the ground.
I mentioned slopes more as I would guess that's when the lockers are more likely to be engaged other then bogholes and the like.
That's my say anyway.
AnswerID: 15574

Reply By: Joe - Wednesday, Mar 19, 2003 at 16:45

Wednesday, Mar 19, 2003 at 16:45
If it is an either/or situation then put the air locker in the front.

If you put it in the back you lose the handling advantage that a LSD gives you on the bitumen.

Mind you, Toyota LSDs are recognised as being a little limited in their effectiveness anyway (read “rubbish”), but you might as well take advantage of whatever you can.

Steering – yes, you lose some steering capability, but as you will only ever use your air locker on very loose surfaces this is not likely to be the problem you might imagine.

Steep slopes – well yes there is some merit to that argument, but IMHO it does not outweigh the advantages of having the front locker and a LSD.
AnswerID: 15590

Reply By: Kev. - Wednesday, Mar 19, 2003 at 20:28

Wednesday, Mar 19, 2003 at 20:28
Ive been told Toyotas ecpecialy Prado can break the front diff when used in the front and not the back. (may or may not be true)
Thats why the twin air locker wiring only allows you to select the front locker if the rear one is allready on.

Also the LSD in Toyotas dont last that long anyway plus what advantage does the LSD have on a 4wd onroad ?

My opinion is to fit the air locker to the rear and if using a mechanical locker fit it to the front to eliminate anoying clunking around corners as most people probebly drive 90% on road.
AnswerID: 15616

Reply By: Tom - Wednesday, Mar 19, 2003 at 20:33

Wednesday, Mar 19, 2003 at 20:33
I often see this sort of question being asked and obviously different responses are always given.
My personal thought is that it should be put in the front - EVEN IF YOU ONLY HAVE AN OPEN DIFF IN THE REAR!!!
The reason I think this is that normally if you are climbing a hill all the weight transfers to the rear helping with traction on the rear anyway, but the front is often left scrambling and spinning trying to find traction with the reduced weight - in my experience 1 front wheel will usually lose traction altogether and instantly turn your rig into a 2 wheel drive!!!I can see an argument for having a locker in the rear of a vehicle with limited wheel travel that constantly found itself with getting a wheel up in the air but then it would probably be wiser to spend money on a suspension upgrade than on a locker.
My own car (60 series Cruiser) has a Lock Rite in the front and an open diff in the rear - suits me fine...

AnswerID: 15617

Reply By: Member - Royce- Thursday, Mar 20, 2003 at 00:29

Thursday, Mar 20, 2003 at 00:29
Here's the theory that I have been given.... makes sense to me: When you are having trouble in mud, sand etc your wheels tend to hill in front. If you have the lockers on the front they pull you up and over the small hill of material. Having said that though.... I have lockrites on the back only of my supatrupa because, forget four-wheel-driving, I need them for two-wheel traction if I pull off the road at some wayside stop or in particular in irrigation country where unknown to me the sprays have hit the side of the road. I haven't engaged the hubs. I'm not in 4WD. I get bogged and then have to get into 4wd to get out. With the lockrites I can go places in 2WD that I couldn't in 4WD and of course a lot further now in 4WD. Hmmm I just read this back ..... a bit garbled.... but it is after midnight. Goodnight. Cheers RoyceRoyce www.funshow.com.au
AnswerID: 15650

Reply By: Member - Graham - Friday, Mar 21, 2003 at 21:30

Friday, Mar 21, 2003 at 21:30
Adding a traction device is always an advantage, BUT always respect the components there attached to ! they will be weaker than the locker.

As for fr/rr Tom is correct that the front near on always is wanting for traction in differcult situations.

My 1st 80 had one in the front a friend of mine had one in the rear
Imagine rutted hill 12" rock ledge to climb over??
In this condition the front could steer and climb, the rear got to the rock ledge but the winch had to be used. Most situations the front fitment had the advantage.

Steering is affected in both to varying degrees when locked, but thats what the buttons for, and you would get use to a slightly different driving technique for either.

My current 80 has twin lockers and sometimes front only would be better.
AnswerID: 15815

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