|
|
Post by noxangelus on Oct 28, 2007 18:56:17 GMT 11
Hey, well after buying new Hubs for my Mu and rebuilding the hubs I finally got a chance to use 4x4 for the first time. I don't think 4x4 has been engaged for many years. My question is, when 4x4 is engaged on sealed roads should there be like a airplane sound? Its not that loud but its noticeable and sounds like an airplane turbine engine and it winds down when slowing down and the noise winds up when accelerating. Also at low speeds below 20 when turning my car wants to stop, I guess its because of the different ratio's of the tyres footprints on the road surface. But the airplane noise worrys me a little, do I need to check the oil in the axle etc? One of the hubs had its locked mechanism stuck in lock for i'm guessing years...(previous owner)  |
|
|
|
Post by noxangelus on Oct 28, 2007 19:01:42 GMT 11
I should mention that only with the gears in 4x4 does it make the turbine sound. When its out of 4x4 and both hubs are still in locked, the noise stops.
|
|
|
|
Post by dasnoboarder on Oct 28, 2007 21:17:29 GMT 11
You should never use 4x4 on sealed roads where the tyres cannot slip on the surface (good traction).
4WD is different to AWD in that there is no centre differential, meaning front and rear driveshafts in tradtional trucks like our Isuzus turn at the same speed. They cannot be turning seperate speeds when in 4wd and the hubs are locked.
Someone will be better at explaining, but as the tyres (and driveshafts) cannot slip, the driveline can bind up, and cause things to break, like the gear box...
Could be the source of the airplane noise.
Andy.
|
|
|
|
Post by geeves on Oct 29, 2007 6:14:52 GMT 11
Never ever use 4wd on a dry sealed road. Its questionable on a wet road as well. Also make sure you have the same tyres front and back with the same tread depth. A neighbour fixes cars and had a Mazda Marvie dropped off for a clutch. He was haveing trouble pushing it into his drive so we gave a hand. As soon as the steering wheel was turned the car stopped and no amount of pushing would budge it. A quick look at the hubs found them locked and in 4wd. We could then tow it down the drive. Clutch was ok but gearbox was history.
A little noise is ok in 4wd but not lots. Start by changing the oil in both diffs the gearbox and transfer case and see how it goes.
|
|
|
|
Post by noxangelus on Oct 29, 2007 7:07:50 GMT 11
Damn didn't think it was that serious!
Could have the airplane turbine sound been the tyres on the road, the back thread is a few mm's less than the front.
It seemed ok going in a straight line, just turning tightly like doing a 3 point turn seemed like the hand brake was on.
It dosn't say not to drive on dry roads with 4WD in the Isuzu Mu manual, it says.. "if the vehicle is being driven in 4WD on dry roads and the steering is fully turned the vehicle may brake suddenly. 'This is not a fault'. Straighten the front wheel or place it in 2h" I find that abit miss leading.
Cheers
|
|
|
|
Post by mudgrip4 on Oct 29, 2007 13:37:33 GMT 11
Are you sure noise is coming from your transfer case? Sometimes when free wheeling hubs are not binding properly they will give some most unpleasant noises. Also there will be a bit of a whine sometimes when in 4wd - old landrovers used to be quite noisy in it.
Do the oils first, then if noise still there, try jacking up front and back on blocks if poss (or better still on garage hoist) - then rotate wheels straight and round onto full lock both ways - check for noises - a stuffed wheel bearing can give a whining noise. Then engage 4wd and hubs and check this again for rubbing/noises. Then start motor and run in 4wd low 1st/2nd and listen again. Should be able to determine where noise is occurring from transfer case forward, unless it only occurrs under load. If so, road test with the rubber boots for gearsticks out - should help isolate it.
Mike
|
|
|
|
Post by geeves on Oct 29, 2007 13:49:36 GMT 11
Isuzu boxes are strongly built compared with the mazda so my example is a worst case senario but if your tyre treads are different you are putting a big strain on things and might be causeing the noise.
If mudgrips ideas dont help try dreiving on a gravel or mud road and see what happens.
|
|
|
|
Post by noxangelus on Oct 29, 2007 15:31:09 GMT 11
Yeah I've got mud tyres with low tread so their a big foot print right now. I dunno whats causing the airplane sound but it sounds pretty cool lol
|
|
mudslinger
Isuzu Junior
needs more curry
Posts: 105
|
Post by mudslinger on Oct 30, 2007 14:14:11 GMT 11
i no wat noise you are talkin bout i get it wen i am in 4h drivin on shingle in between 4wd tracks.only in 4h tho and only wit speed.
|
|
|
|
Post by geeves on Oct 30, 2007 19:56:53 GMT 11
There shouldt be any real noise in 2wd or 4h and only a small whine in 4l. Have you tried driveng in 4h with the hubs unlocked. It might produce a clue
|
|
