Separate front and rear diff e-lock switches?

I'm sorry if this has been covered, it's just a thought I had before I head off to bed. My 93 has the switch for the e-lockers. You must engage the rear locker before it will allow you to engage the front. Can I wire this into two switches, one for the front and one for the rear? If so is there really and point in doing so? I figure if this is a dumb idea you all will shut me down in a hurry before I go and do something stupid or pointless.

Thanks in advance,
Aaron

Actually, forget I asked. I was looking over the G-class Mercedes and although it has individual switches it seems to call for them being engaged in the same way as the Cruiser works. I'm guessing there is a very solid reason for that.

I would imagine that it's doable, but as you suggested, why?

the truck is permanent 4WD with open diffs (usually) so if one wheel slips, the Centre diff lock (CDL) is often enough. That sends the drive equally to front and rear. If a rear wheel slips, the the front will pull you through and vice versa. CDL is normally automatically switched when in Low ratio.

The only time you may need the axle diff locks is when it's very muddy particularly on inclines or when the ground is undulating to the extent that you're lifting wheels on flex, then they can be brought in.

The front axle diff lock makes steering very heavy and causes loss of grip on cornering (that's why there's a diff there!) but in a straight line it's very effective. It's designed as a last resort IMO.

When the front is locked, steering can be dangerous, so take care.

I wouldn't recommend changing the F/R set up, but I'm considering taking the auto CDL off the Low and keeping it optional in L as it is in H as standard.

Someone more experienced will be along to explain the wiring, 'cos that's a mystery to me

The system is designed that way, as Clivehorridge points out I too would prefer to use them as a last resort but as an asides, I prefer to ensure they are engaged BEFORE they might be needed not when I find I need them, I would rather not get stuck in the first place. Another point to be aware of is the front differential on the 80 is not the toughest out there.

I have fitted the centre diff lock switch of earlier models, the main reason is when reversing a heavy trailer up and incline and needing low range the damn CDL would engage and cause biding as I would be turning/reversing on tarmac, the tyres screeching was the clue.

With the CDL switch I can decide to use the CDL or not, another advantage when 'Rambla racing' (dry river bed), you can engage the CDL in high and this in turn switches OFF the ABS, ABS is something you do NOT want when on unstable surfaces.

regards

Dave

Sounds sensible enough. I've already installed the CDL switch and disconnected the automatic engaging of same in low range. I've just fallen in love with tinkering with the truck and I've about run out of things I can do with a non existent modification fund. I'll leave well enough alone as far as the lockers go. Thanks for the advice.

Aaron

Sorry Aaron, from your last post, it seems I was trying to "teach my Grandmother how to suck eggs" if that means anything to you!

Logically, it would not be any advantage, for example, to have the front axle diff locked when the CD and the rear axle diff were still open.

I imagine it's for this reason that Mr T (and maybe recognizing that the front diff is not the toughest on the planet), sought to bring them in sequentially, CDL, then RR, then Front.

TBH, I wouldn't recommend changing that, only the change you've already made to de-select the CDL in Low.

Now, if you were building an all-out rock crawler, or something more specialized, then the story may well be very different indeed

I wouldn't. As someone who used them constantly (until this week tht is), you'll find that the front one doesn't add nearly the same benefit as the rear one. If you can get through with the centre and front locked, I would think you'd have got through it with only the centre! Adding the rear locker gives much greater grip and as Clive says, leaves your steering lighter. With your rear unlocked you would effectively loose all rear drive as one wheel spins and the other doesn't move.

Also when in mud etc, I would NOT lock them first. I appreciate the not getting stuck principle, trust me, but with everything engaged you tend to drive in deeper and further before you are stuck and then you've nothing left. I go in fully open, just the viscous coupling of course, then if I feel like I have lost traction, try to reverse out, if I can't I put the CDL in to get out. I might then try a little further knowing I have the rear locker and front locker to go at too. Now sure sometimes the hazard isn't that bad and you can bang everything in and go for it. But in something like deep snow drifts, I go with the progressive option to lockers.

Some good points on using the lockers Chris however, apart from traction your next best friend is momentum, if you lose traction then you lose momentum, add to this you have already spun wheels and perhaps dug a ditch lowering your ground clearance. I suppose everyone has their thoughts on this, I gained mine via competitions and it seems the general method to get through obstacles is traction combined with momentum, just my opinion.Sorry I would have replied earlier but for some reason this site keeps freezing and I keep getting a long running script error, only happens on this site and I have reported it via the contact us/site issue link.regardsDave

Arguably there's a not insignificant difference between "competition" and normal off-roading though

Doodle said:

Arguably there's a not insignificant difference between "competition" and normal off-roading though

Click to expand...

I take your point on that Doodle.

After my recent experience of a failed Birfield, I'm going to think twice next time I'm tempted to lock up the front diff.

I'm going to go Chris' method of CDL then maybe RR. After that I'll get the winch line out

OE birfs are very strong and rarely fail but, these trucks are getting old now and over the years most owners will have used components of inferior quality during repairs, add in bigger wheels/tyres and you move out of the design parameters. If there is a weakness on the 80 it is the front differential, in particular in reverse. If you go abroad where these vehicles are still used for humanitarian aid HDJ 105 (80 chassis 100 body but IIRC illegal in the EU due to BS about emissions) you will find they are as near as dammit stock mechanically, drivetrain failures are pretty much unheard of.......no matter how hard you try.

regards

Dave

Clive,

I suspect once you've fixed it, measured use of front diff lock will be fine. Drivetrain parts wear and fail, usually you only find this out when put to the test (i.e. engaging diff lock)