4WD problemette...

[Thomas-the-Terrano2]

on a a part time 4x4 same place we all do when you throw the lever into 4hi.

locks the rear output shaft to the front one, even on auto hubs this is the
point of no return, split second later the front prop via the diff and the half
shafts locks the front wheels via the auto hubs. once these locked all front
end spins like your fixed hub front end, providing you dont reverse in 2 hi
auto hubb'ed front ends will continue to be spinning waiting for that old dog
clutch to kick in.

the transfer lever combines 2 separate functions of engaging 4wd and
high to low. on some boxes its possible to split the functions, via twin lever
conversion. handy if you wanted to shunt heavy on hard surface, though
care would be needed due to torque doubling effect of low box. the same
effect can be unofficially enjoyed with manual hubs as the 4wd spin all
way down to the unlocked hubs but the front wheels would get the drive.

for more fun could fit manual hubs to rear axle and simulate front wheel
drive or save the rear prop on a suspended tow, like an enhanced version
of truck being in neutral in transfer box....

[lacroupade]

Aaaah - Thank you Grasshopper.

[tezzer]

Originally Posted by lacroupade

oh but that sounds like hard work Pete, and its cold

But I'll try and get a diagnosis first then maybe break out the 20 year-old mmmmmmm...in fact forget it, I'll just drink the port and buy a Landie LOL

2 bottles paul, and pete will supply and fit it for you, might take awhile though, he will probably be pi**ed.

[solarman216]

Originally Posted by Thomas-the-Terrano2

on a a part time 4x4 same place we a providing you dont reverse in 2 hi
..

You can reverse in 2 hi and 4 wheel drive will not disengage, it will only disengage once you stop driving the shafts from the box, Rick

[kbekl]

Originally Posted by solarman216

You can reverse in 2 hi and 4 wheel drive will not disengage, it will only disengage once you stop driving the shafts from the box, Rick

if you reverse in 4wd with hubs locked it will unlock and then relock, and upon going forwards it will unlock and again relock as the locking hubs are directionally locked

[rustic]

Originally Posted by lacroupade

....right, no barrack room mechanics please, need someone who knows their way around the diff/front drive

When I engage 4WD on my fixed-hub Mk IV I get a kind of low frequency whining and mild vibration, and the truck seems to want to wander slightly off to the right.

There are no symptoms in 2WD and apart from the noise, 4WD does function normally otherwise.

At the moment I suspect the CV joint - wheel bearing would be noisy in 2WD and it isn't - but is there anything else in the drive chain up front that might be the cause?

And if it is CV, how costly are the bits does anyone know?

Cheers m'dears....

I've read all the threads, but I assume you are on a slippy surface when you do this, as you will get wind up if all 4 tyres are not exactly the same, pressure, tread depth, and make etc.

Yesterday I was out in the mav, auto hubs engaged, slipping in and out of 4 wheel drive, and on a straight section of ice covered road, I tried the brakes, and the Mav stopped quite easily without any skidding.

So maybe the slippy stuff isn't as slippy as you first thought, thus the wind up.
A few winters ago I was in Minesota and the temperature was -20C and the ice under foot was not slippy, I was wearing smooth soles at the time and the ice was as hard as concrete, and as grippy, I was very surprised.

If you took a glass of water throw the water into the air, it hit the ground as ice crystals. At -30C you can do the same with red wine. (What a waste)
Never tried it with Malt whisky, unless it was inside me first....

[lacroupade]

Originally Posted by rustic

I've read all the threads, but I assume you are on a slippy surface when you do this, as you will get wind up if all 4 tyres are not exactly the same, pressure, tread depth, and make etc.

Yesterday I was out in the mav, auto hubs engaged, slipping in and out of 4 wheel drive, and on a straight section of ice covered road, I tried the brakes, and the Mav stopped quite easily without any skidding.

So maybe the slippy stuff isn't as slippy as you first thought, thus the wind up.
A few winters ago I was in Minesota and the temperature was -20C and the ice under foot was not slippy, I was wearing smooth soles at the time and the ice was as hard as concrete, and as grippy, I was very surprised.

If you took a glass of water throw the water into the air, it hit the ground as ice crystals. At -30C you can do the same with red wine. (What a waste)
Never tried it with Malt whisky, unless it was inside me first....

Damned thing has been doing it everywhere,from wet roads, through a foot of snow on the autoroute to sheet ice on the way up to my house in wales, with no variation

[rustic]

Originally Posted by lacroupade

Damned thing has been doing it everywhere,from wet roads, through a foot of snow on the autoroute to sheet ice on the way up to my house in wales, with no variation

Well I guess all your front running gear has done many more miles than mine, so it could be CV's or bearings as the bearings will be under more strain while being driven.
Front prop shaft UJ's spring to mind and there is also the sliding coupling as there are 3 grease nipples on the front prop shaft.
If you greased the 3 grease nipples, you may feel a difference, but for a very short time as the grease is squeezed out.
There is more wear somewhere than there used to be, might even be the rear drive train as well.
There are just too many items that when worn will cause this problem, having looked at the other threads.

[lacroupade]

Originally Posted by rustic

Well I guess all your front running gear has done many more miles than mine, so it could be CV's or bearings as the bearings will be under more strain while being driven.
Front prop shaft UJ's spring to mind and there is also the sliding coupling as there are 3 grease nipples on the front prop shaft.
If you greased the 3 grease nipples, you may feel a difference, but for a very short time as the grease is squeezed out.
There is more wear somewhere than there used to be, might even be the rear drive train as well.
There are just too many items that when worn will cause this problem, having looked at the other threads.

thats what i'm afraid of, hence the pre-garage diagnostic. but less than 100k miles on this lady so just not sure.

I'll let you know how she gets on in the garage

[rayf3262]

If your 02 front prop is anything like my 02 front prop - don't be to surprised if there are no grease nipples.
As for the sliding coupling; it's now coated in a high tech plastic that is self lubricating, it does wear though, and this can give rise to vibration of the front prop.

[lacroupade]

Originally Posted by rayf3262

If your 02 front prop is anything like my 02 front prop - don't be to surprised if there are no grease nipples.
As for the sliding coupling; it's now coated in a high tech plastic that is self lubricating, it does wear though, and this can give rise to vibration of the front prop.

interesting tip, thanks. no vibration though, just this infernal low-pitched whine and "I-want-to-go-right-you-ba5tard!" from the steering....

[rayf3262]

Originally Posted by lacroupade

interesting tip, thanks. no vibration though, just this infernal low-pitched whine and "I-want-to-go-right-you-ba5tard!" from the steering....

The: "I-want-to-go-right-you-ba5tard!" is easily fixed!

[lacroupade]

Originally Posted by rayf3262

The: "I-want-to-go-right-you-ba5tard!" is easily fixed!

true, but not that attractive when you're trying to keep straight in a foot of snow while some Portugese w*nker in a 40-tonner is overtaking you on the other side (and yes, he was wrapped round the central reservation three miles down the road I'm pleased to report)...

[11redrex]

Hope you said obrigado

[lacroupade]

Borrox.

Garage has been great, not charging me for two hours+ spent on diagnosis but they didn't want to waste my money on labour costs.......the boss has now driven it extensively, and after me explaining to him how the T2 suffers badly from tranny windup in the dry, has eliminated the usual suspects and potentially narrowed it down to the transfer box which is gonna be another big expense to rectify FFS

Just to remind people, in case there are any more suggestions, symptoms are:

1. Nothing untoward in 2WD.

2. A low frequency whining/moaning in 4WD that increases with vehicle speed......sounds like its coming from front left.

3. Noise is worse under strain but vanishes completely on very slippery surfaces.....e.g. it will be howling at 45mph on a wet road, but soon as you hit snow, silence....!

It all sounded like a bearing but its such an odd phenomenon that its really difficult to pin down......so at this point its gonna be 'run it til it breaks' (that or sell it .

Meantime though I might look at a scrapper for a late tfr box but if anyone has any other alternate diagnosis.....?? (Remember its a MkIV with fixed hubs).

Cheers