Strange noise when in 4x4 - can anyone identify it?

[Vomitbomb]

Hi all,

Wondering if anyone can help me identify this noise? It’s like a *tink tink tink* when in 4x4 only and particularly when the wheels are turned (see video). Mechanic doesn’t believe it’s a CV. I haven’t noticed it until recently but after having the transfer case replaced I’ve become increasingly sensitive to random noises the car makes. Is it normal?

FYI I do have an auto lokka in the front but I don’t remember the unlocking sounding like that.

https://youtu.be/qVVGBuMQ9nA

Cheers.

 

[Old.Tony]

It was actually difficult to identify the sound. There was a sound of the drive train binding causing the wheels to slip and that's not unusual even without a locker.

There was a ta-ta-ta-ta-ta sound in there as well, somewhat metallic - now that could have been a few different things.

* Transfer case chain. Unlikely unless the car's been driven a lot on firm surfaces in 4WD. The chain stretches and eventually the slack side taps away at the housing.

* Transfer case output bearing. Not as rare as we'd like. The seals go, dirt gets in and the inevitable happens. Inspect and check the drive shaft ends for play. Note that in the D40, the front drive shaft turns over whether the car is in 4WD or not, but there's no pressure. With the car up on a hoist with the wheels free (chassis lift) and the engine off you'll hear it. You can also grab the drive shaft and shake it - either the uni will flop or the end shaft will flop.

* Front drive shaft uni joints. Common. They're exposed. The more dirt/sand driving you do the more the risk. Easy to diagnose, as above.

* CV joint. Not common. If the CV boots are cared for, they're pretty hard to kill, although lifting a front wheel and allowing it to spin just as it drops and bites is a surefire way to kill the CV, the front axle or the diff itself. Hoist as before, turn over each of the front wheels while listening to the CV area.

* Front diff. Not common. They're a light duty diff, the previously mentioned wheel lift can destroy them. Examination on a hoist is necessary, a mechanic's stethoscope is useful. If the diff is fitted with an auto locker it may just be the auto lock engaging and disengaging, don't mis-diagnose a failing diff from the auto lock mechanism.

* Front wheel bearing. Common. 4WD or 2WD doesn't really matter, but 4WD puts more strain on it and makes it easier to hear. Easy diagnosis too (in 2WD). Find a nice smooth corner that you can take at about 50-60 km/h in both directions without tearing up the tyres (eg a 55km/h corner taken at 60km/h). Listen carefully to how the car sounds in the left hand corner, then turn around and do the corner the other way and listen again. If the car makes more noise in the left hand corner, the RIGHT front wheel bearing is shot. Vice versa for the other. My own car did this, but I don't recall hearing a ticking sound in 4WD at low speeds, mostly because I only engage 4WD in slippery situations or when wading at hub-deep or higher (and good luck hearing anything when the wheels are under water).

 

[jonney]

the tick tick noises are coming from the stones on that drive area. at least test the vehicle on a sound tar surface.

 

[Vomitbomb]

It was actually difficult to identify the sound. There was a sound of the drive train binding causing the wheels to slip and that's not unusual even without a locker.

There was a ta-ta-ta-ta-ta sound in there as well, somewhat metallic - now that could have been a few different things.

* Transfer case chain. Unlikely unless the car's been driven a lot on firm surfaces in 4WD. The chain stretches and eventually the slack side taps away at the housing.

* Transfer case output bearing. Not as rare as we'd like. The seals go, dirt gets in and the inevitable happens. Inspect and check the drive shaft ends for play. Note that in the D40, the front drive shaft turns over whether the car is in 4WD or not, but there's no pressure. With the car up on a hoist with the wheels free (chassis lift) and the engine off you'll hear it. You can also grab the drive shaft and shake it - either the uni will flop or the end shaft will flop.

* Front drive shaft uni joints. Common. They're exposed. The more dirt/sand driving you do the more the risk. Easy to diagnose, as above.

* CV joint. Not common. If the CV boots are cared for, they're pretty hard to kill, although lifting a front wheel and allowing it to spin just as it drops and bites is a surefire way to kill the CV, the front axle or the diff itself. Hoist as before, turn over each of the front wheels while listening to the CV area.

* Front diff. Not common. They're a light duty diff, the previously mentioned wheel lift can destroy them. Examination on a hoist is necessary, a mechanic's stethoscope is useful. If the diff is fitted with an auto locker it may just be the auto lock engaging and disengaging, don't mis-diagnose a failing diff from the auto lock mechanism.

* Front wheel bearing. Common. 4WD or 2WD doesn't really matter, but 4WD puts more strain on it and makes it easier to hear. Easy diagnosis too (in 2WD). Find a nice smooth corner that you can take at about 50-60 km/h in both directions without tearing up the tyres (eg a 55km/h corner taken at 60km/h). Listen carefully to how the car sounds in the left hand corner, then turn around and do the corner the other way and listen again. If the car makes more noise in the left hand corner, the RIGHT front wheel bearing is shot. Vice versa for the other. My own car did this, but I don't recall hearing a ticking sound in 4WD at low speeds, mostly because I only engage 4WD in slippery situations or when wading at hub-deep or higher (and good luck hearing anything when the wheels are under water).

Thanks for the detailed reply Tony.

Yep it’s that metallic noise I’m interested in. I first noticed it when I was in the Simpson desert - not the best place to hear something unusual. The D40 is actually at the workshop now for unrelated issues (timing chain and injectors )so I’m unable to check those things you mentioned just yet.

Just before the trip I had the transfer case replaced with a second hand one from the wreckers after the breather tube came off my original and decided to suck in a bunch of water, dirt and sand over time (installed a breather kit after that). There was eventually so much movement in the parts that the chain started slipping (how the mechanics described it) and that made a horrible noise. It felt like it was binding up then releasing, if that makes sense. Anyway, I hope it’s not the replacement that has issues already.

I also replaced the front right hub shortly before the trip. That actually did sound like a stone/s in the tire (amplified) and was very noisey around a bend as you described. I actually jacked the car up and shook the wheel. It moved a ridiculous amount. I was thinking of replacing the other side too just to get it out of the way. Perhaps it’s better just to have one spare.

I actually started wondering if it could be the lokka itself but it still seems to be working flawlessly.

 

[Vomitbomb]

the tick tick noises are coming from the stones on that drive area. at least test the vehicle on a sound tar surface.

I wish it were just stones it first presented itself while driving on sand. I’ve replicated it on grass too.

Don’t think I wanna be doing that on a tar surface. Wouldn’t wanna ruin another transfer case (if it’s not ruined already).

 

[jonney]

your not going to damage a thing by testing this noise issue on a hard quiet surface. what i meant by the stone drive way area is you really can,t hear what you want to hear other than the tyres rubbing over the stones.

 

[tweak'e]

i'm thinking along the lines of the auto lokka.
the are meant to unlock during a turn when you have no or low power on.
it may be a case of you are hearing it now due to hot weather making the oil thinner.

 

[Vomitbomb]

your not going to damage a thing by testing this noise issue on a hard quiet surface. what i meant by the stone drive way area is you really can,t hear what you want to hear other than the tyres rubbing over the stones.

Sorry Jonney I misunderstood.

Yes you’re right I should find a surface that’s not so noisey so it’s a little more obvious. Perhaps when I get the car back if Tony’s suggestions don’t end up revealing anything.

 

[Vomitbomb]

i'm thinking along the lines of the auto lokka.
the are meant to unlock during a turn when you have no or low power on.
it may be a case of you are hearing it now due to hot weather making the oil thinner.

Thanks Tweak. Hadn’t thought of that. Aside from spinning the wheels while the car is jacked up I’d never noticed the sound of the auto lokka. I was always surprised it was so quiet after reading reports from other people.

If there’s no obvious faults when I get the car back I’m wondering if I should just keep driving it and see if anything gets worse or breaks. I may just be overly paranoid.

Alternatively I’ll take it to a 4x4 place to get looked at. I’ll see how I go once these other issues are sorted out but that seems to be taking forever.