The Mitsubishi Pajero Owners Club®

rjcpng · * Joined: 23 Oct 2011 Posts: 14 Location: Papua New Guinea

G'day all,

I have an NH Pajero 4D56 Automatic, living in a muddy country. Here's my symptoms:

When I put the car into 4WD, and go on the straight and level, everything is fine. 4WD works and gets me out of trouble. But...
When in 4WD, and braking down a mud hill, I hear a "click" sound coming from the front wheel. I used to think it was coming from the wheel hub, but after closer listening it seems to be from the front diff. I have the car in L gear, which is still not enough to slow it down, and therefore need to apply brakes as well. When the weight of the car is borne by the brakes in 4WD mode, I get this click.

It is a definite click, happening I would guess every 1/4 revolution of the tyres. I'm going at slow speed to retain control on the greasy mud. It feels like the car has not got as much traction when it clicks.

The other time I can notice it is, if I park the car (i.e. put it in P), and then give a forward push on the car by hand, I get the same click. This happens even in 2WD.

Any ideas where to look and what it could be?

Cheers!

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peteinchad · Posted: Thu Dec 18, 2014 11:24 Post subject:

Maybe a CV joint is worn.

trekker · Posted: Thu Dec 18, 2014 13:27 Post subject:

When you're in 4WD on this muddy hill, turn the steering into a tight circle and accelerate slightly. If the problem is worn CV joints, the clicking will be pronounced and frequent.

Let's hear what you find.

rjcpng · * Joined: 23 Oct 2011 Posts: 14 Location: Papua New Guinea

The clicking sound happens regardless of whether I'm turning or going straight. It doesn't sound like a typical CV joint - I've heard other cars turning a U-turn and the typical "clack", but this I would describe more as a "click", not a "clack" if that makes sense. It doesn't occur during acceleration, only when the axles are bearing the full weight of the car, i.e. the heaviness of the car wants to make it go faster down the hill, but the low gear ratio is holding the car back and slowing it down (using the gears for braking effect).

I will have to go out and test turning tightly on the hill while accelerating, but the roads are so narrow here that it'll put me in the ditch. I'll have to find a suitable place. But from what I've observed before, if the engine is accelerating the car, I don't get the click. It's only when the gear ratio is braking the car, putting strain through the drive train, that I've noticed it. Could it be a missing tooth from a gear in the diff etc?

I'm just in the process of pulling the CJ joints apart, so I'll see if anything is wrong inside. How can you tell if CV joints are worn?

rjcpng · * Joined: 23 Oct 2011 Posts: 14 Location: Papua New Guinea

OK, just opened up the Front Diff cover. Everything seems ok inside, except a very fine spring which was dangling loose inside the diff. I think it must be the spring around the LH oil seal. which keeps it tight. I'm just wondering: could the clicking be from the Free-Wheeling Clutch? Maybe it's not engaging properly? Can someone explain how it works? It seems to be by vacuum.

NJV6 · Posted: Fri Dec 19, 2014 8:03 Post subject:

Yes it is vacuum, it pulls against a spring to hold it in 2wd so when/if you even loose vacuum, you keep 4wd as it is the default. This is why sometimes you get the front wheel lights flash on engine start up, as it has to activate 2wd again.

There is a short axle (about 4-5 inches) and a sliding slip joint which when in 4wd slides a collar across and joint the short axle to a longer axle. The inner cv bolts onto this longer axle. When in 2wd your crown wheel and pinion in the front diff are not turning when everything is working properly.

They can click as they disengage, mine does when I turn the engine off as it engages, especially if there is no load on it so it can disengage.

Sorry, no idea on your click, transfer case? Every 1/4 of a turn of your wheel makes me think transfer case, driveshaft universal joint etc, anything that is spinning 'faster' that the wheel if you get my drift.

trekker · Posted: Fri Dec 19, 2014 8:41 Post subject:

The drive axle CV joints have 6 steel balls in a cage splined onto the shaft, and on the other shaft a spider. The steel balls run in grooves on this spider enabling the two shafts to bend at the joint, whilst still providing a constant velocity drive.

When these grooves develop a wear pattern, the steel balls click into and out of the grooves, hence the noise. This though is not usually heard the the straight ahead position, only when the joint is run at a different angle.

So it's not likely to be these CV Joints giving the noise.

rjcpng · * Joined: 23 Oct 2011 Posts: 14 Location: Papua New Guinea

Thnks for replies. I am just about to pull my CVs apart tomorrow and regrease, reboot etc. I will take a good look and see if anything is obvious.

T1ny · Posted: Sun Dec 28, 2014 2:13 Post subject:

did you have any luck with this? my car is doing something similar,

rjcpng · * Joined: 23 Oct 2011 Posts: 14 Location: Papua New Guinea

OK, further update. I have checked the CV joints and nothing obvious. I pulled apart the FreeWheeling Clutch, and found 4 of the needle bearings fallen out of the bearing housing and sitting lose. I cannot be certain whether they've been like that for some time, or they fell out when I pulled the shaft out. However, I did also find a metal filing about 2 inches long also in there, like a thread of metal which is obviously worn off. I can't see where it came from, because all the parts have no sign of wear; I can only assume it is from the needle bearing housing, which is obviously worn enough to allow the roller bearings to drop out.

I have confirmed that the "clicking noise on park" is simply the Freewheeling Clutch locking into place upon park, with a slight movement of the car making the gear teeth mesh / engage. I guess this is normal behaviour?

For the "clicking in 4WD down a hill when car is under its own weight", I still am not sure the cause. What I am going to do is put the wheels back on, then listen again and see if it still happens. I need to somehow stick my head under the car while it's moving and locate the source of the noise - whether the transfer case, the Freewheeling / Diff, or the CVs - not an easy thing to do I guess.

I'm describing it as a clicking sound, similar to using a ratchet, and that's how it feels too - like something's jumping something. Remember, I'm not travelling at high speed; I've got the car going at a snail's pace to keep it from sliding out of control into the ditch. It only happens when the car is under its own weight and in 4WD; i.e. the gear ratio holding the car back from going the speed it wants to go under its own weight.

Will update more as I find out more.