T4 diff lock (EDL)

[Silver Caravelle]

Hi Seano,

Absolutely they are two different hings.

The electronic differential lock (EDL) for the non 4 wheel drives is really just an 'electronic' limited slip diff ( sort of a basic traction control) linked to the ABS and not so much a 'lock' as you indicate.

It is tied to the ABS to monitor if one front wheel is spinning faster (i.e. skidding) than the other front wheel. The ABS is applied to the faster front wheel transferring the power to other front wheel for wheel speeds over 9 to 10km/h when the ABS is activated.

Cheers,

Scott

[Jezza]

yeah Seano, very different to mine. I have attached a photo to show you my rear diff. Taken from behind showing diff and left hand wheel. Can you see the mechanism, the small motor and the gear housing.

I am very envious that you can store your spare wheel underneath.

On the air filter indicator, the fact that my indicator is not there tells me that they may have removed the panel with the air filter indicator and the diff lock switch too maybe??

Does anyone else out there have a 2000 model ex NSW ambulance/patient transport vehicle that I could compare notes with?

Did you have to change the drive shaft in any way to lower the diff because of the slightly longer length required, like actually lengthen it or lower one of the rear drive shaft mounts. Or was there enough movement in the drive shaft to allow for the lowering of the diff.

[Jezza]

Ok. For those that are interested, I have had a revelation. I was on the vwt4forum.co.uk forum at;

http://www.vwt4forum.co.uk/showthrea...ight=diff+lock

they had a webpage that deciphered all the codes in your drivers manual, namely;

http://igorweb.org/equidec/Default.aspx

I punched all my codes from my book into the website and came up with all the details of my vehicle. turns out that mine has the following;

1AD = Anti-lock brake system (ABS) with electronic differential lock (EDL)

Sounds good. Now all I need to know is, should it have a dash mounted operation switch or is it automatic? Hmmmmmm

If it is automatic Seano, I now know why it goes so well in the sand of WA. It is unstoppable over here.....

[jets]

You obviously didn't click onto the link that I posted earlier on this thread.
Did you learn about any other options your van has from the PR nos?

[Jezza]

No I must admit I read that message and didn't have a clue what you meant by 'PR no 1AD'!! I realise now obviosly.

Any idea if the diff lock should be automatic or should it be manually operated.

Apart from the obvious like 'steering wheel', 'four wheel drive and 'LWB', I learn't that it has an 'increased payload', 'Alternator 90A' and 'Transmission ratio, high geared'. I was hoping that I had a 110kW motor but it only turned out to be a 75kW. I am very happy with power. It has plently enough for me at 75kW. I can't quite beleive how much power it has actually, plently of overtaking power and it accelerates well when needed.

[jets]

I should have explained that PR means optional equipment. I came across the term in elsawin but was able to work it out after reading the owners manual.

I don't know anything about the rear diff lock actuation, you may have to ask your dealer.

I thought my alternator pushes out 120A. Can't find my notes just at the moment.

[Seano]

yeah Seano, very different to mine. I have attached a photo to show you my rear diff. Taken from behind showing diff and left hand wheel. Can you see the mechanism, the small motor and the gear housing.

On the air filter indicator, the fact that my indicator is not there tells me that they may have removed the panel with the air filter indicator and the diff lock switch too maybe??

Did you have to change the drive shaft in any way to lower the diff because of the slightly longer length required, like actually lengthen it or lower one of the rear drive shaft mounts. Or was there enough movement in the drive shaft to allow for the lowering of the diff.

Thanks Jezza.......yep.......you have a rear diff lock. And I am hell envious. Although since you don't know whether it is activatable or not (or even permanently on - not a good idea) then I'm not sure how great that is!! Only way to find out is to get all wheels off the ground and turn one of the rears. If the other side turns then you have a problem.....but only a minor one - mostly to do with fuel economy. CORRECTION my handbook says it shouldn't be used above 45km/h and an acoustic warning signal should sound on vehicles equipped with ABS when you do.

Diff lock switch should have been up on the dash in the switch line with aircon, rear window heater etc.CORRECTION......my vehicle hand book shows that the difflock switch (a pull knob plus an indicator) would have been on the same panel as the air filter saturation display.

Fitting the spacers required nothing else to be modified - it was to correct the drive shaft angle so the drive shaft couplings (which are flexible) don't wear out prematurely as a result of the lifted rear suspension.

[Jezza]

Yeah, I am pretty excited about it. It wouldn't be on permanently otherwise something would have gone bang by now. It would defeat the purpose of having a lock I suppose, 'lock' meaning on and off capability. My manual says the same about the pull out lever/switch. I have followed the electrical wires but cannot find where they enter the engine bay or under dash. I have pulled the under side of the dash covers out and have found no evidence of unused wires, colour coded to the diff lock or otherwise to indicate that there is a missing switch.

The diff lock also has a vacuum line. I have followed vac line and it connects to the main vac line going to the barake booster. As I mentioned before, the fact that the air filter indicator was disconnected, I found the purple vac line under the dash too by the way, disconnected behind the heater controls, tells me that some where along the line the air filter indicator and possibly the diff lock which was removed and maybe not put back. Hmmmm.

I have a copy of elsawin now, the VW program with all the vehicle details. I haven't managed to get it going as yet. Having a few dramas with it.

Also Seano, in front of the diff on the tail shaft there is a large circualar device, 1800mm dia. approx. 250mm long which I assumme is the tail shaft vicsous coupling. I also wonder if this is lockable by the diff lock mechanism as well? From your photos on pg. 1 mine looks longer than yours. The way my diff is set up, it looks like it could be operable from the diff lock mechanism....i'll take a photo of it shortly.

Diff lock or not, I am impressed where this vehicle can take me. Maybe then the diff lock is automatic....

[Seano]

Jezza

The fact that the diff lock operates via a pull out switch suggests that it uses a vacuum line to the switch from the brake booster.....not electrical leads.....basically it's a tap. Exactly the same as the one in my old Range Rover - it uses manifold pressure to activate the central diff lock. So you may be looking for at least two vacuum lines.... alternatively you are looking for an electrically operated in-line tap.

That big circular device is, I assume, some sort of driveshaft balance come flywheel. If you poke your hand in behind the rubber flange you'll find a large hollow area.....probably filled with rocks and sand!! There's nothing there to lock.

[Jezza]

Thanks Seano. There are two vac lines coming out of the diff lock mechanism. One heads straight to the engine bay, I'm happy with that, the source vacuum, the other comes from the mechanism and is then 'tee' peiced into the top of the actual diff housing then runs a bit further into the sub chassis and I can't find where it goes after that. There seems to be another vac line from else where, ABS system perhaps that is connected by a small cover into an electrical line. Vague I know but I will get under there now and have a good look and let you know.

If the diff lock is vac operated, I assume then the electrical connection is just a warning and indication light for the dash....