Whats the sequence for engaging 4WD on a townace or doesn't it make any difference?

Stop the vehicle
Lock the wheels
Press the 4WD button on the dash
Play around with the stick next to the autodrive
Set off again.

The reason I ask is the blue 4WD light on dash doesn't appear to light up with pressed and the 4WD gear stick refuses to move from "high" to "low".

Any idea's???
Thanks

- (#11845) Phil, 30 Jun 04 02:52

That's near enough it yes. First the front wheels need to be locked. This Locks the normally free wheeling front hub on to the drive shaft of the front axle. Then 4WD can be switched on and off by the button on the dash but you don't have to be stationary to do that, its ok to do it below about 20mph I think. If the 4wd button is not lighting up then it may be a vacuum problem, a blown light in the switch, a blow fuse, or something more serious. The high low ratio gear stick is in essence a manual gear with no clutch or syncromesh. This makes it a bit difficult to transfer between the ratios, and you need to have the handbrake on and the gear lever in N I think.
- (#11845) dave Bright (Bournemouth), 30 Jun 04 03:36

The fact you can not shift to low range is an indicator that you are not getting 4WD.
It may be as simple as moving the vehicle in 4WD for a short distance - sometimes they don't engage until you have a turn on the wheels.
For a test leave the hubs UNLOCKED, and then push the button, and roll the car foward in drive about a meter.
The light should now come on. With the light on and the vehicle in Park, try the low range lever - it should move relatively easily.

A little warning - when changing back to high range, make sure you push the lever all the way to front - there is an unmarked neutral position that will only give you horrible sounds and no drive at all!

There is a safety trap in that you can only engage low range after 4WD is on, and only in Park or Neutral.

(Note: I said to test with the hubs unlocked to avoid 'wind up' - the system will still work fine, and will not be damaged - but it does NOT give 4WD without the hubs locked in! This way the test can be done on the road!)

- (#11845) DaveW, 30 Jun 04 19:45

Yes, the 4WD switch controls a solenoid-operated valve (in the door pillar by the sliding door) which applies vacuum to a servo to connect drive to the front axle. Once it is connected the blue 4WD light comes on. If it hasn't been connected for many months then it can get quite sticky and take some time (a minute even) and or jolting around to get it to work, and likewise to disengage later. As daveB says this assumes that the electrical connections are OK, the vacuum pipes are connected up correctly, and the 4WD bulb is working.

The 2nd gear lever is nothing to do with 4WD except that you can't engage "Low" unless in 4WD. It engages a reduction gearbox that affects drive to both axles. I use it (with 4WD switched on but front hubs not locked) for driving slowly on/off ramps and even just to get going up a very steep drive when I've just started a very cold (diesel) engine.
- (#11845) Dave Mason (Sussex), 1 Jul 04 02:59

i know low ratio can't be selected unless in N or P, but once driving in low ratio, can you then change to high. ie. starting on a steep hill, do you need to stop at the top, change to N change to high and then off again, or can you just change to high when you get to a suitable speed. didn't like to try, just in case!

- (#11845) eddie arrowsmith, 1 Jul 04 16:19

4WD can be engaged at wpeeds up to about 60kph, but Low range should only be engaged/disengaged with the vehicle at a standstill. (and as you mentioned in N or P ;^)

A word of warning (not to you DaveM but to everyone else!) that running in Low range without the hubs locked puts massive torque through the driveline (relatively speaking!) and if you are not gentle you can damage the rear diff/ driveshaft etc. just be gentle!

- (#11845) DaveW, 1 Jul 04 19:53

Not sure about the warning in your last post DaveW.

For Townaces I would have said the opposite, that running in Low range WITH (not without) the [front] hubs locked puts massive torque through the driveline.

... and that warning doesn't apply if you're "off-road", where the tyres will slip and prevent the torque building up.

Is that what you meant to say? This area causes terrible confusion! Your warning would only apply if the rear diff was itself locked by engaging 4WD or Low, whereas it is only the centre diff that is effectively locked when in 4WD (because there isn't a centre diff).

- (#11845) Dave Mason (Sussex), 2 Jul 04 03:59

DaveW is correct. Remember that engine torque is multiplied by reduction gearing. that is, at full load, available torque at the wheels is 1st gear x diff ratio x transfer ratio. Switching from Hi to Lo ratio goes from direct to something like a 1.7:1 reduction, so the propshaft, diff, halfshafts, and tyres, could all conceivably see 1.7x the normal torque...

That's turning force. Driveline bind may well result in the same or indeed higher torque levels.

- (#11845) David Miller, 2 Jul 04 09:10

Sorry if I challenged that warning unnecessarily. But I guess I need to respond again and try to leave this thread in a helpful state.

OK, using Low gives you more torque at the axle - I realise it's not just a way of going at Low speed.

So I agree, the warning is that putting your foot down in Low without the front hubs locked puts powerful drive through the rear diff alone, instead of half on each axle.

I now see, and agree, that DaveW was correctly advising "just be gentle" but I (and I feared other owners might) wrongly read him as saying that it's better to experiment in Low WITH the front hubs locked - which would only be valid off-road.
- (#11845) Dave Mason (Sussex), 2 Jul 04 11:12

Yep sorry - taken in isolation it is not too clear.

I forget that people don't always read the whole thread, and so might miss the earlier bits about 4x4 only on slip surfaces.

My suggestion of testing with the fronts unlocked was because I assumed that most people couldn't just drive out the driveway onto a bit of dirt to test, and the last thing we want is for people to be 4x4ing on the road!

- (#11845) d.winter@aamsurveys.com.au, 4 Jul 04 20:41