Metallic clunk from front of car when downhill in Low Range.

[Red_MAv]

Back from a good day of driving at Licola yesterday and the Maverick climbs anything beatifully but when going downhill in Low range under engine braking there is this massive clunk that occurs every 10 or 20 feet depending on the gradient. It also happens if reversing uphill as in doing a 3 point turn when going down hill. I tried unlocking each front hub one at a time and that made it go away but of course I was in 2wd so no strain on the drive components. Removed the FR manual hub today and it looks in perfect condition. The noise appeared to come from either the RHS or centre of the vehicle a bit hard to tell. Any ideas on where else to look. Its a bit hard to explain but as you are going down under engine braking it go clunk and the vehicle will lurch forward slightly and then keep going down again until it does it again. Its like theres a tooth missing somewhere but uphill nothing happens its all perfect. Any assistance appreciated on this one..

[nzdarin]

Check your body mount bushes.

[jessie928]

Back from a good day of driving at Licola yesterday and the Maverick climbs anything beatifully but when going downhill in Low range under engine braking there is this massive clunk that occurs every 10 or 20 feet depending on the gradient. It also happens if reversing uphill as in doing a 3 point turn when going down hill. I tried unlocking each front hub one at a time and that made it go away but of course I was in 2wd so no strain on the drive components. Removed the FR manual hub today and it looks in perfect condition. The noise appeared to come from either the RHS or centre of the vehicle a bit hard to tell. Any ideas on where else to look. Its a bit hard to explain but as you are going down under engine braking it go clunk and the vehicle will lurch forward slightly and then keep going down again until it does it again. Its like theres a tooth missing somewhere but uphill nothing happens its all perfect. Any assistance appreciated on this one..

sounds like your freewheeling hub/s

JEs

[xenith]

pos diff wind up how long u had her might have two diffrent diffs

[Red_MAv]

Had the vehicle since new it has a rear ARB locker fitted 4 years ago but never made this noise before. I was not using the locker at the time either. I have noticed the Uni's are shot so will replace them but dont know whether that would cause such a noise, at least only going downhill anyway.

[beretta]

I have noticed the Uni's are shot so will replace them but dont know whether that would cause such a noise.

You just picked the problem i reckon, your shot unis.

[ROCKMUTT]

mine was also doing this same thing when i brought it , i pulled the hubs off and they where fine i couldnt find the problem until it went bang last time i was out ,it had a cv that was almost completly worn thru and finally let go on me taking out my cv,stub axle,hub,disc and caliper

i would be pulling it down further and checking it all out mate

[Red_MAv]

I have replaced both the front uni's and also checked the free wheeling hubs. The RHS hub had minor burrs on the edge of the teeth so I filed them all smooth and it appears to engage properly. Found a nice steep hill at Berwick this morning and I'm really pissed because it still makes the noise. Any ideas on what else could cause this. The noise definately seems to come from under the car, not the hubs. Its more of a clunk as something lets go rather than a bang.

[jessie928]

I have replaced both the front uni's and also checked the free wheeling hubs. The RHS hub had minor burrs on the edge of the teeth so I filed them all smooth and it appears to engage properly. Found a nice steep hill at Berwick this morning and I'm really pissed because it still makes the noise. Any ideas on what else could cause this. The noise definately seems to come from under the car, not the hubs. Its more of a clunk as something lets go rather than a bang.

i still think its one of your hubs.

Jes

[Red_MAv]

How can I be sure the hubs are actually engaging. I noticed when I had it out that when you turn the dial to engage it there is a spring movement which allow you to push it back down which could mean when its fitted it may not engage. A mate said there is a chain belt in the transfer case which can stretch over time and slip after a lot of k's. Mine has done 270k but it only slips going down hill. I can see the drive belt/chain he talks of in the Gregorys manual but it doesnt say anything about replacing or adjusting the tension of it, is this possible?

[jessie928]

How can I be sure the hubs are actually engaging. I noticed when I had it out that when you turn the dial to engage it there is a spring movement which allow you to push it back down which could mean when its fitted it may not engage. A mate said there is a chain belt in the transfer case which can stretch over time and slip after a lot of k's. Mine has done 270k but it only slips going down hill. I can see the drive belt/chain he talks of in the Gregorys manual but it doesnt say anything about replacing or adjusting the tension of it, is this possible?

swap some hubs from a truck you know that works so you can know for sure.
If someone actually knows the sound of a hub unlocking exactly, they can tell you straight out. otherwise, just swap some over

a chain skipping on a patrol transfer is highly unlikely

you need access to someone that knows every sound a patrol makes from every part of its drivetrain, woudl make it much easyer than guessing.

Jes

[Red_MAv]

I have access to a GQ with auto hubs are they interchangeable as in just screw on the outer section with my manual hubs.

[jessie928]

I have access to a GQ with auto hubs are they interchangeable as in just screw on the outer section with my manual hubs.

they are interchangeable. interchange the whole part.
when you remove the actual hub, also take off the circlip and swap the gear behind it aswell.

Jes

[Red_MAv]

Had the swivel hub and inner axle seal done yeaterday and the hubs checked out as well. Mechanic says they are fine and that the noise will be the chain in the transfer case has stretched and is slipping under load which is why it only does it going downhill or reversing uphill. A changeover transfer case is around $250 does anyone know if the GU and GQ ones are the same or not. I figure if they are I would be better with one from a more recent vehicle.

[robjohno]

hey how did ya go figuring out your problem?

[JWB]

[quote="Red_MAv"]Had the swivel hub and inner axle seal done yeaterday and the hubs checked out as well. Mechanic says they are fine and that the noise will be the chain in the transfer case has stretched and is slipping under load which is why it only does it going downhill or reversing uphill.

A mechanic I spoke too a few years ago while chasing an unusual noise told me the t-cases are tuff as! he has only seen/ heard of one going bang with a big HPv8 in front of it??
i Would get another opinion before changing the transfer case:?
cheers

[JWB]

have you tried low range down hill with the hubs not engaged?

If the noise is there then at least that takes the hubs out?
if no noise then take another look at the hub/s
cheers
OOPPs! just re-read the original post!
belay this post!
cheers

[robjohno]

yeah i having the same problem as red atm in my swb. big clunk when going down hill in low range 4x4 every 4 or so meters. had to help my god father do a tour last weekend and was all very easy roads but had to do one steep down hill section. high range 2wd needed the brakes too much (all other cars were in low 4x4) , therefor needed the low range, didnt want to do any more damage to what ever was the problem so didnt lock the hubs. no clunking. so problem is only under load. hopefully i get time to get my mechanic to look at it this week.

[Tuflux308]

Had the swivel hub and inner axle seal done yeaterday and the hubs checked out as well. Mechanic says they are fine and that the noise will be the chain in the transfer case has stretched and is slipping under load which is why it only does it going downhill or reversing uphill. A changeover transfer case is around $250 does anyone know if the GU and GQ ones are the same or not. I figure if they are I would be better with one from a more recent vehicle.

pretty sure they are gear driven... no chain, i think surfs are chain driven but not GQ's

[Red_MAv]

No noise at all with the hubs unlocked. Even unlocking one at a time different sides releases the front of all the 4x4 load. Reversing back up a step hill gives the same noise. Only have to travel a couple of metres and bang then on you go, it sounds awefull and from under the centre of the car. GQ definately has a drive chain in the trfr case its shown in the Gregory's manual.
I must admit I am sure hoping the trfr case changeover fixes it because I dont want to then chuck on new hubs as well.

[Red_MAv]

Also just because most mechanics say they have never seen one go or they rarely have problems, doesnt mean they dont I guess. 95% of Patrols would never do the work we do in ours and as such would never have it show up. Even if I flogged mine to someone as their daily driver it works a treat. Unless they take it down a really steep hill they would never know there was an issue with the transfer case.

[Red_MAv]

Its FIXED. Had the transfer case changed over today at Wombat Offroad in Ringwood and took it for a drive up a steep hill near home tonight, hooray, no more clunk. So it looks like it wasnt the hubs or the Universals (which needed changing anyway) but the transfer case slipping. Not too expensive either at under $600.

[da60]

Another thing to be aware of is that his noise can also be caused by flogged out radius arm bushes (body end) as when you go either downhill of stop for driveway/kerb you will get the same noise when the front wheels strike the object!!!