Isuzu Trooper Owners Club UK™

[Jamelle]

I have recently purchased a 1994 Trooper Duty 3.1TD with 140k on the clock. It is equipped with auto locking hubs.

Panic soon set in, however, when I put it into 2WD. After a very short distance, a noise which I can only descibe as the sort of noise you used to get by sticking a lolly stick into the spokes of your bike wheel when you were a kid but louder, could be heard coming from the front off side wheel. I stopped, put it back into 4WD and carried on - noise goes away.

In addition to this (as if things weren't bad enough) when reversing in 4WD there is a loud bang which feels as though I've run over a brick.

Any takers?

[Google]

[markymoan]

Welcome to the club

You are driving in 4wd on the road
You may have wound the gearbox up and caused permanant damage,
I'm sure one of the more techy minded will be along soon, and i hope it isnt terminal.
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[Jamelle]

Thanks for the reply. I take it from that, it's a no-no to drive in 4WD on the road?

[markymoan]

The gearbox winds itself up like an elastic band because nothing can give, if that is your problem you could try jacking all 4 wheels off the ground so it can unwind, but as i said one of the more technically minded WILL be along even if i have to drag them
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[Philp]

As Mark said, don't drive it in 4wd on hard surfaces. When you put it into 4wd the front and rear axkles are locked together, when you drive around a corner the front and rear wheels travel a different distance, normally in 2wd this isn't a problem as they are free to do so. In 4wd they have to move at the same rate so you put a lot of stress into the driveline that can do all sorts of nasties such as break gearboxes, axles,driveshafts or even twist a propshaft. To get the stresses out either jack up all four wheels at the same time and let tem spin or find some mud and go and give it some welly and let the wheels slip about.

I would say the noise you have is coming from the free wheeling hubs. In 2wd they effectively disconnect the wheel from the driveshaft so you aren't stirring the front diff around thus saving a modicum of fuel. When you put it in 4wd they automatically lock the wheel to the driveshaft when you drive for a meter or so. To unlock them you need to change direction for a meter or two so if going forwards put into 2wd and reverse a few meters, the opposite if you've been reversing.

It may purely be that the noises are down to the wind up and it will stop when you get the stresses out or you may have knackered this hub by driving in 4wd on tarmac, or it may just be worn out. The auto hubs on my MK1 were knackered and used to slip occasionally when off road with an enormous bloody bang, scaring the pants off me. I replaced them with a set of manual hubs from Milners or you could find a used set of free wheelers. If you intend off roading a lot manual lockers are better as once they're locked they're locked. If you get stuck with auto lockers and need to rock it back and forwards the flipping hubs keep locking and unlocking when you shift direction which is not ideal.
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Phil

96 or is it a 98 Isuzu Bighorn Lotus

[Jamelle]

Thanks for all that, I will try and find some mud as I don't have four jacks!

[Philp]

Try just jacking up the back axle, you only need one decent trolley jack under the diff in the middle. As lon as it's in 2wd it should work.
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Phil

96 or is it a 98 Isuzu Bighorn Lotus

[jonkem]

Any wind up will have gone when & if the hubs were unlocked as the front shafts can spin freely. If the noise is only when you are in 2wd but with hubs still locked, it can only be because you are driving the front axle via the front wheels ie. the drive to the axle is coming from the wrong direction. Because in normal use this is no problem for the front end, it would suggest damage to the diff or transfer case. As Philip says, this damage is very, very easy to inflict with wind-up.

If you have reversed the car for a couple of metres and the noise is still there when going forwards (all in 2wd), it is most likely to be the hubs.

If it has been driven on good surface in 4wd for quite some time, it is unfortunate but fairly likely that the front diff and or transfer case are damaged
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1994 KZJ70 Cruiser (currently filling the garage and causing some head scratching)
1988 MKI 3.1td Hybrid Van (Ex Bobtail)
1991 SWB Fronty 2.8td Hybrid
2000 Astra Estate (work)
2006 VXR Astra
MK1 SR Nova

[markymoan]

jonkem, the hubs wont unlock if its wound up
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[Jamelle]

Sorry for not getting back sooner, I had to go off to work and now I've read the threads I wish I'd stayed there!

If the hubs arn't unlocking how do you know?

Where are the correct places to put the jacks if I go for the option of jacking it up to get all four wheels off the ground?

[markymoan]

you could just jack the rear end, make sure its in 2wd and the front is chocked up to stop it rolling off, then put it in gear and run it for a min (handbrake off)
Then drop it off the jack and reverse for about 15-20 ft
Then grab one of the front driveshafts and check if you can turn it by hand, if you can then its unlocked
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[jonkem]

Mark,
for the hubs to not unlock after reversing for a distance in 2wd, you are talking about forces that none of the transmission can withstand. There is nothing with enough elasticity in the transmission that can store energy for that long.

Assuming the car is being driven on normal road journeys, it will experience a fairly equal amount of left & right turns which it can possibly survive unscathed for very short periods.

In an extreme case a LR was driven round and round a roundabout with hubs & centre diff locked. I think it was only the fourth rotation when the car flipped onto its side due to wind up. In more normal cases you will loose traction on the tyres or break the transmission before it gets that bad. The steering will also try to centre itself.

The jacking method is only ever necessary if the transmisson is fully locked due to wind-up and the car cannot be driven or you cannot disengage 4wd.

Next time you are on a large flat area of grass, flick it into 4 low and go around in very slow (tickover) full lock circles while leaning out the window and looking at the front wheel. You will then see the amount of wind-up you have to loose on each revolution. We used to use this method on training days, having pupils watching from outside the car looking at the bottom of the wheels. You will see a wheel jerk about 50mm on each quarter circle, which is all the wind up it can stand on a grass surface
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1994 KZJ70 Cruiser (currently filling the garage and causing some head scratching)
1988 MKI 3.1td Hybrid Van (Ex Bobtail)
1991 SWB Fronty 2.8td Hybrid
2000 Astra Estate (work)
2006 VXR Astra
MK1 SR Nova

[markymoan]

OK i'll shut up and go back to fixing things
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[jonkem]

My front bearings are waiting for you Mark Got a real problem with one of the little buggers. Looks like a bad part supplied
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1994 KZJ70 Cruiser (currently filling the garage and causing some head scratching)
1988 MKI 3.1td Hybrid Van (Ex Bobtail)
1991 SWB Fronty 2.8td Hybrid
2000 Astra Estate (work)
2006 VXR Astra
MK1 SR Nova

[markymoan]

Dont start,,, I dream blummin bearings now
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