four wheel drive mode...problem??

[petrolhead63]

my 2.8TD has just had an issue put right by my local garage following a problem caused by their mechanic and you know what it is like, can never remember quite how a car felt before!!

Problem was I was lazy and got them to do the lower ball joints because it was cold outside! should have done it myself and avoided this lot. Within 13 miles it had self destrcted its ABS ring on one hub, wrecked the sensor and backplate and disc and also would not engage 4 wheel drive.

The ABS and ring is sorted and the 4 wheel drive it turns out that one of the auto lock hubs fell apart when they pulled the hub out a bit to remove the ball joint, they managed to assemble it with a washer the wrong way round. The proprietor (not the boys) spent a long time working this out (not knowing his staff had actually dismantled the auto lock hub!) by looking at the other side.

I am not sure if it is correct now. It engages 4 wheel in both ratios fine but if driven it has a lot of resistence if you let it coast, enough to make it come to a halt with clutch dipped or in neutral with a slight nose dip as though a brake is binding, I do not remember this before but to be honest in 4 wheel drive it is usually slow in grass an like. The extra set of drives obviously causes a drag but is it this much?

Perhaps some of you can put my mind at rest and say it is common like that (I dont remember my 2.3TD like it?) or suggest it has a fault and what it is.

In summary it engages and drives fine in 4x4 but feels like a brake binds when coasting to a halt and the nose dips as it stops....obviously not free wheeling well.

[alex]

Can I just ask, is it fine in 2wd coasting? In 2wd the hubs, tranny and Front diff arent involved. Also are you on grass/mud/dirt for the 4wd test or tarmac?

[petrolhead63]

in 2wd it is absolutely free to roll, in 4wd it has the "drag".......must say test is on tarmac and gravel drive but four a walking pace roll it makes no difference I guess. To drive in 4 wheel on tarmac up to about 25mph it does create a fair bit of front wheel tyre squeel and pull a bit to the right, but the tyres are not my usual ones having fitted a set of old sport wheels and tyres and it has smaller front tyres so all 4 being driven may cause a bit of tramlining.

It is the sensation of a binding if you try and freewheel I am unsure of and I wonder if it is more drag than the diff,transmission etc should create?

I hope I stand to be corrected!

[alex]

1. Dont use 4wd on tarmac. It will create wind up in transmission and break allsorts.

If your test on tarmac needs a rolling start you could be winding the transmission up, when you drop to walikn pace the tension is there already.

I would suggest trying on something slippy then report back.

[alex]

Just read your post propperly, Different sizes front to rear.... think thats your problem. Dont use 4wd or you WILL break something.

[petrolhead63]

yes I am aware of wind up although I thought it would only become an issue with a lot longer drive on tarmac. Can it be unwound? sounds silly but for example by jacking the car up all 4 wheels off the ground?

It would be nice to be sure it has no wind up present.

Out of interest why will the different tyre sizing front to back be an issue?......is it the poossible slight different rolling diameter?

[alex]

The Frontera has a none permanent 4wd, unlike Disco's etc there is no diff front to rear, its a live axle to speak of. So if the front is smaller diameter it will turn more times than the rear, given a couple of revolutions and the tranny will be wound up.

The same will occur side to side.

As for jacking it up when its stopped, you may need to jack both fronts up to release the windup. If the right hand side is the noisy one its because the half shaft is much smaller and wont tolerate wind.

[petrolhead63]

your knowledge is great........I am a good classic car man but less experienced with 4x4. I have just researched wind up an it seems a drive in 2wd is supposed to dissipate or unwind any wind-up, I think I shall replace the other wheels with same size (although huge 255x55x18 awful) tyres and give it another go.

It could be winding up as you say within a few meters causing the problems. I will report back in time after it is done.

I had thought wind-up became noticed when the drive locked and had not realised it can simply cause a binding feeling prior to this.

Thanks.....any other thoughts appreciated.

[alex]

No problems mate,
If your running different sizes in 2wd then other than the sort of geometry issues you will be familiar with its a personal thing. Just glad you didnt persevere and break anything, use the site, its got all the info you will need. Dont be afraid to ask, we all drop clangers, me especially.

[weave67]

me too hide the "ommer"

[alex]

the mighty ommer, seems to have a mind of its own over in Wolvo. Bit like my sawn off sledge, for big damage in tight area's

[weave67]

i do damage with rubber mallets too

[alex]

mallets mallet BOING!

[petrolhead63]

we all do silly things!..........I can recall late one night in the dark years ago in the rain and fed up laying a 1/2 inch drive wrench straight across the battery posts! I had such a shock I stood bolt upright (I'm 6'4'') and smacked my head on the bonnet! My mate who was helping by standing around gassing with a cup of tea was no use as he was in fits of laughter

[alex]

Oh yes, electricery and metal. Had many a fond time with a mega and foolish individuals .

[petrolhead63]

well, its all lovely jubbly now..........put back on the big BK racing wheels but having advantage of same size tyres all round!! so the old mud plugging/boat launch set need a pair of fronts to match the back.

[Silver Ghost]

[petrolhead63]

no, never have two size spares! but on the basis most moderns have a space saver that is not the same size as any and limit you to maybe 50mph I figure wrong size will get me out of trouble!......though I'm sure the law will tell me it is all wrong!!

[Red Oktober]

the law says you must not have different sized wheels on the same axle

[Rich2.4i]