T4 diff lock (EDL)

[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....

[Seano]

There seems to be another vac line from else where, ABS system perhaps that is connected by a small cover into an electrical line.

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

The 'other' line into the diff is probably the sensor hooked into the ECU (which mine has)

The electrical connection at the switch is almost certainly just for the dash mounted warning light but it must hook up to your ECU at some point given you have ABS and the book says that in vehicles with ABS an audible signal will sound if you go over 45km/h with the diff lock engaged.....

[irsa76]

The missing airfilter gauge and difflock switch can be easily explained. On some vans the Ambulance upfitter added the extra radios on the lower dash, where the gauge would be. I've also seen some early vans with the switch panel there as well, iirc there were a couple of companies doing the conversions. As for the difflock, chances are it was disconnected early in the vehicles service. Ambulance drivers aren't known for being gentle on equipement, you should see the carnage they caused on the Sprinter 4wds!

[Jezza]

Thanks for your reply. Any ides who the ambulance upfitters were. There may be a chance that the dash peices are lying oround in their warehouse. Wishful thinking I know but one must try

[Seano]

Jez........somewhere in a bullbar post is a link to the dudes that do/did NSW ambulances....

[Jezza]

Cheers Seano. I'll have a looksee....