Metallic ringing noise

[Chris078]

My truck has developed a hideous ringing/vibrating noise coming from around the gearbox area.
As far as I can tell, it's not actually the gearbox. Doesn't feel like it's grinding/slipping at all.
My mechanic thinks it's actually in the exhaust, but seeing as how is doesn't really start making noise until you hit a hill in 2 or 3 or get on the highway, it's proving more than a little difficult to track down.
I'm going to drop the oil in the gearbox and transfer case in a bit and see if there is any sign of trouble.
you can barely hear the sound at idle, and it doesn't get louder if you rev the car in neutral. It's particularly bad in 3rd and 4th gear at speed, but if you take your foot of the throttle (but leave in gear) the noise goes away.
I don't know if there is a loose bolt vibrating somewhere, the gearbox or front diff is eating itself, or if something else is going on.
I just know that it is really annoying.
If anyone has any ideas, I'm all ears.

Now, a couple of questions.
1. The PTO and Transfer box are combined, yes? so when I drop the oil, I just need to fill one spot rather than 2? (capacity of 5.8L with winch)

2. Transmission oil capacity is only 2.7L ?! (just making sure, seems a low amount for such a big transmission.

3. Front Diff 1.7L of 80w/90 (this (http://www.supercheapauto.com.au/online-store/products/Castrol-EPX-Differential-Manual-Transmission-Fluid-80W-90-4-Litre.aspx?pid=1115#Recommendations) is what I used last time, I hope that is correct)

4. Wheel bearing. (99% sure it's not a wheel bearing, but hey....)
Do Perenties have a wheel bearing grease nipple? If yes, where is it and what grease to use. If not, how do you grease the bearings.

5. Swivel hub bearings: mine have had the grease conversion.
*how to you check if they need greasing?
*how do you grease them (I think you need these (https://www.google.com.au/search?q=land+rover+one+shot+grease&biw=1440&bih=803&tbm=isch&source=lnms&sa=X&ved=0CAcQ_AUoAWoVChMIiIGAipiixwIVJS2mCh12sQHj&dpr=1.33) but how to use etc)


I think that's all. No doubt I'll be back later with more questions or a tale of woe[happycry]

[BadCo.]

My exhaust had a lose bolt and it sounded like a metallic ringing.

I am also interested in the answers to your swivel hub questions. I am pretty sure there is a square bung on the top and bottom for filling/emptying (as can be seen in the rps)

Waiting for someone clever to come along..

EDIT: More reference material. This guy makes great videos!
https://www.youtube.com/watch?v=y6AO6dsNGGM

[Blknight.aus]

the ringing is tinnitus....

the ringing you are describing is usually one of three things... the heater/vac pipe mounting clamp, the exhaust mounts or flange or the air filter housing mounts.

it an also be a loose bolt/nutsert in teh roll cage or the cam net frame on the roof. and in the case of an FFR something in the cubby in the back of the bulcked in the loadspace floor or a battery mount for the FFR battereis


main geearbox take 2.7, tcase takes upto 5.8 depending on varient same main casing two oil level check locations

80/90 front and rear diffs.

checking the grease is a dip with a zip ties while at full lock so the swivel all is clear of the hole, there is no grease nipple on the wheel bearings, they are grease d like your trailer bearings theres a hand full of cheats for cheking and replenishing without stripping but do yourself a favor and check out some of the threads o the topcs of grease VS oill for the hubs and bearings.


the grease for the wheel bearings is XG274 which you wont get so use castrol lipex or similar wheel bearing grease. the stuff your putting into your propshafts and rod ends is fine.

f

[MVFrancis]

One more thing to check is the shields behind the brake discs. I had a similar tinny sort of sound for months that was nearly the death of me; turned out to just be a loose bolt on one of the shields in the end.

[Chris078]

Thanks Blknight.
Quick question, when you say 'rod ends'; what exactly are you referring to?

also, I noticed that none of the ball joints on a Perentie are greasable. Are they designed to run dry, or is there some magic trick to greasing them?

[Phil B]

You can grease them using a needle attachment on a grease gun
You can get them from Supercreep
Phil

[Chris078]

You can grease them using a needle attachment on a grease gun
You can get them from Supercreep
Phil


Cool. Do you just poke the needle through the rubber. or is there a specific spot?

<edit> is supercreep an intentional misspelling?

[Phil B]

Yes and yes

[Chris078]

I think I've identified the problem.
The heat shield over the exhaust manifold is resonating. The noise is then travelling down the exhaust pipe which made it hard to track down as depending on the frequency of the vibration, different parts of the pipe would resonate as well.


I have no idea how to fix it though. I pulled it off (one of the the stud nuts was very loose but the gasket still held luckily) and put it back on making sure all the nuts were tight; still resonates.

Is there such a thing as heat proof rubber washers?
either that or I'll have to weld on a strip/bar of aluminium to it along the outside to stop the vibration.

[BadCo.]

Could you do away with the shield and use exhaust wrap?

Sent from my Nexus 4 using AULRO mobile app

[Chris078]

Could you do away with the shield and use exhaust wrap?

Sent from my Nexus 4 using AULRO mobile app


I picked up some reflect-a-shield today. looks like a flexible tube made out of the same stuff as a windscreen sun reflector but apparently is good for 1000f continuous radiant heat.
We shall see if it works on the weekend! :)

[Blknight.aus]

Thanks Blknight.
Quick question, when you say 'rod ends'; what exactly are you referring to?

also, I noticed that none of the ball joints on a Perentie are greasable. Are they designed to run dry, or is there some magic trick to greasing them?

When I said rod ends I ment the tie rod ends the ones on the steering rods that attach to the ball joints which are also reffered to as swivel pin housings,

Do NOT grease anything by poking a needle through the rubber or the seal.

I reccomend that you eyeball barefootdaves book, it covers some of the maintenance.

If that doesnt help I think that incisor has the emeis available for purchase on CD from his shop.

[Chris078]

The search for the noise continues. Having taken off the heat shield (which was definitely making a resonating noise) the noise is still there, so it was not the source.

Listening to it today in various places with the old mechanics headphones, it does seem that the exhaust is ringing (which would make some sense as the noise gets louder as everything warms up). Next step will be to remove the exhaust at the manifold and see what happens.

Going to the mechanic on monday for brake and clutch fluid change. Ox-8 seems to be DOT-4 fluid, can anyone confirm that this is correct?


Also looking through the service manual, it advises to lube the water pump if it is fitted with a nipple..... can anyone point me as to where to look for the nipple?