GQ Patrol Rear end squeal

[White Elephant]

Okay, so now that the formalities are out of the way. I have a very annoying intermittent squeal (almost sounds like the whistle that a boiling old school kettle makes) in the rear end of the old bus. I have replaced the rear wheel bearings & seals (twice...thought I might have got some dodgy bearings...I like to bargain hunt) and brake pads, pulled apart, lubed it and put it back together countless times and the noise is still there.

It pops up intermittantly after driving for an extended period of time. I have pushed in the clutch pedal when it starts just to make sure it's not throwout noise, applied the skids at various speeds to make sure it's not a brake issue, and done some hard left to right steering and vise versa to try and find the source of the problem. On occasion the sharp steering jolts will stop the noise momentarily and then after a minute or so it will start back up. I'm totally puzzled. If anyone has any ideas please let me know!

[Sir Roofy]

have you checked diff oil might be a bearing in the diff its self if you have done a lot of clicks they may be getting a tad tired

[White Elephant]

have you checked diff oil might be a bearing in the diff its self if you have done a lot of clicks they may be getting a tad tired

Good call! I keep all the diff & trans oils well changed, but I didn't even think about that...Kinda thought it would have been a wheel bearing before the indestructible mechanism that is a Patrol diff. So you reckon maybe drive pinion bearing? The noise has been hard to pick between left and right side, it seems to change up at will...though it could just be resonating through the diff and axle housings. It's an LSD btw. Oh and she's just rolled over 341k km's.

[Sir Roofy]

Good call! I keep the all the diff & trans oils well changed, but I didn't even think about that...Kinda thought it would have been a wheel bearing before the indestructible mechanism that is a Patrol diff. So are you reckon maybe drive pinion bearing? The noise has been hard to pick between left and right side, it seems to change up at will...though it could just be resonating through the diff and axle housings. It's an LSD btw. Oh and she's just rolled over 341k km's.

could be a pinion bearing if the the cover is a bit loose or grit or water found its way in

or maybe the sound is going down the tail shaft, chasing sound is hard at the best of times

[White Elephant]

could be a pinion bearing if the the cover is a bit loose or grit or water found its way in

or maybe the sound is going down the tail shaft, chasing sound is hard at the best of times

I concur. Muchos Gracias Senore. I'll have a play around on the weekend and see how I go. If I get a result I'll let you know!

[Sir Roofy]

I concur. Muchos Gracias Senore. I'll have a play around on the weekend and see how I go. If I get a result I'll let you know!

noworrys mate was just a thought hope it pans out well for you

[White Elephant]

noworrys mate was just a thought hope it pans out well for you

As do I! Hopefully nothing too serious, generally squeals and groans aren't, but this one has me perplexed...

[patch697]

Have you thought to check your park brake drum?

Although you said its coming from the back, noise will travel through the drive train especially in a full chassis.

[White Elephant]

Have you thought to check your park brake drum?

Although you said its coming from the back, noise will travel through the drive train especially in a full chassis.

I haven't checked it recently, but I did sus it out a few months back before this dilemma. might be worth another look regardless. Cheers.

[White Elephant]

Okay, so I spent the best part of my Saturday morning with the bus up on the hoist. I dropped the tail shaft off to make sure the uni joint and drive pinion didn't have any play in it, and also to make sure the drive pinion flange seal wasn't leaking(you can do this from inspection only-no need to pull the tail shaft off),as well as making sure the flange itself was done up to FT(I assume some of you understand FT) torque. Check. All is well.

I then ran her in 3rd gear with the rear end lifted(with wheels on)for about 15 minutes to see if I could replicate the noise. However, the noise didn't return. So I took the wheels, rotors and calipers off, deglazed the rotors, and brake pads, cleaned everything up, and on a whim decided to run her in 3rd for a bit with the wheels off before I put it all back together.(At this point I should let you know that the hub seals etc showed no signs of leaking either,usually there would be a build up of cr@p inside the rotors and obvious signs of leaking around the hub)And bam, the noise came back. So after putting the stethoscope all over the place to try and pinpoint the noise, I have come to the conclusion(with agreeance from my mechanic) that it is possible that the actual bearing housing may be worn, and the race is skidding around inside the housing. As posted earlier I have replaced the bearings twice just to be sure it wasn't the bearings.

So, I got jack of it, cos I felt like a beer and watching some footy, so I put everything back together and will further investigate the problem in the next week or so. Will pull the axle out(again)and see if the diagnosis is correct. Will keep you posted! Cheers to Roofy and Patch for the tips, but it is definately something going on in the bearing housing.