Diff and drive shaft question

[dom14]

Hi guys,
I've been trying to locate the place and cause of the deep grinding or grunting kind of a noise coming from the car. It's a GQ patrol 20+ years old. manual transmission with RB30 motor. The car appears to have gone through a suspension lift. Currently I got 225/75 R16 tyres on it.
I measured the distance between chassis rail and the edge of the rear tyre is 8cm on left side and 9cm on right side.
There's a clearly visible upward tilt of the diff as you can see in the picture. I'm not sure whether this is right or not.
Is this caused by the suspension lift?
Can this cause excess wear on uni joints and the diff?!
Can this be the reason for grunting I hear on low revs and on 1st and 2nd gear when taking off the car?
Thanks for any help.

[MudRunnerTD]

when was the rear Uni fitted? It looks like someone has been working on the car?

The angles look ok but really hard to tell from a couple of pics. maybe more description of the symptom would be helpful mate.

Cheers MR

[BigRAWesty]

I'm guessing you have stock panhard rods? If so as you lift it the rods will lower in an arc, pulling the axle to one side, thus the 1cm difference.

And the diff looks to be inline with the tail shaft which is fine.

So I'd say probably not.. how old is the clutch?

Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

[pearcey]

Check the engine and exhaust mounts. With engine flex or torque the exhaust or some other part may be touching the body

[dom14]

when was the rear Uni fitted? It looks like someone has been working on the car?

The angles look ok but really hard to tell from a couple of pics. maybe more description of the symptom would be helpful mate.

Cheers MR

Hi mate,
That someone is me. I cleaned the uni's and greased them, but haven't changed them. But, it didn't make any difference. I basically did a thorough job on all the uni's(4 of them, front and rear) by taking the shafts off the ca, then cleaned and greased on a bench using a gun.
I used the right type of grease as well.

Noise is low pitch deep growling kind of noise, only appears during take off on low revs on 1st and 2nd gears. It only last for less than a second. I will try to record it and upload here.

Location of the noise, from the direction of the noise and the feeling on my butt while I'm driving tells me it's more of a noise somewhere around the gearbox and clutch.

I'm wondering whether the fly wheel was bit damaged by a bad clutch in the past?!!

Clutch appears to be fine at the moment.

[dom14]

I'm guessing you have stock panhard rods? If so as you lift it the rods will lower in an arc, pulling the axle to one side, thus the 1cm difference.

And the diff looks to be inline with the tail shaft which is fine.

So I'd say probably not.. how old is the clutch?

Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

Hi mate,
Yes, the panhard rods looks like pretty old & they aren't adjustable, so I reckon they are stock ones.
The bushes looks ok as well. I replaced front end bushes not that long ago, including engine mounts.

Do I need to fit adjustable panhards if the distance to the tyres from the chassis rails is not the same?!

Car's been with me for about four years now. So the clutch is definitely older than that. Clutch hasn't been bad for the past four years. I can't adjust the clutch, can I?! It's a hydraulic one. I'm guessing all the GQ's come with hydraulic clutches!

Do you think it may have a damaged fly wheel from a bad clutch in the past?!

[Clunk]

Sorry can't remember from your other thread but did you say you've changed all the oils? Transfer, diffs, gearbox etc????

Don't stroke it, TAP it!!!!.....

[BigRAWesty]

To be honest. Duck knows... And I'm guessing your not really wanting to pull the gear box off just to look.. haha.

What rpm range are we talking? Does it happen if you change into second at a higher rpm?

Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

[dom14]

Sorry can't remember from your other thread but did you say you've changed all the oils? Transfer, diffs, gearbox etc????

Don't stroke it, TAP it!!!!.....

Yes mate. Only front diff oil I left as it is, 'cos it was as good as new, and I rarely use the car on 4WD. gearbox, transfer box, rear diff all got new oil.

[dom14]

To be honest. Duck knows... And I'm guessing your not really wanting to pull the gear box off just to look.. haha.

What rpm range are we talking? Does it happen if you change into second at a higher rpm?

Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

I reckon, the growling comes on around 1000 ish rpm(or less) and lasts less than a second, then I shift to the second gear, depend on the load(like going up hill or taking a sharp turn) then it growls on second gear too, but agian for less than a second.

I'm suspicious of the clutch(or flywheel rather I guess), but I'm thinking the suspension lift that was done might have been a half hearted job. 'cos the rear diff is obviously not in the centre of the chassis rails distance. Panhards look like the factory ones, not the adjustable ones.

May be I should install an adjustable one and adjust the distance first?

BTW, no I wouldn't wanna pull the gearbox, mate. That's beyond my equipment abilities at the moment. I dont' have an engine crane or tranmission trolley adapter yet. Three months from now, I will have room to keep a one. :)

[Big Red]

It sounds like the normal 1000/1100 rev rattle that all TD42's have.
I believe it caused by the clutch plate springs rattling at that particular rev.

nothing to worry about but go test drive another one and compare if you really want to.

[taslucas]

It sounds like the normal 1000/1100 rev rattle that all TD42's have.
I believe it caused by the clutch plate springs rattling at that particular rev.

nothing to worry about but go test drive another one and compare if you really want to.

It's an rb30.

Dom, I wouldn't worry about the diff being slightly to one side. If you wanted you could fit an adjustable panhard rod to bring it back to centre, but I'm sure there are plenty of patrols about that are sitting the same as yours.
As for the rumble/grinding noise, does it do it only when letting the clutch out ti move forwards or would it make the same sound if you stopped on a slight incline then let the car roll forward with the clutch still in?

FanTapstic!

[dom14]

It's an rb30.

Dom, I wouldn't worry about the diff being slightly to one side. If you wanted you could fit an adjustable panhard rod to bring it back to centre, but I'm sure there are plenty of patrols about that are sitting the same as yours.
As for the rumble/grinding noise, does it do it only when letting the clutch out ti move forwards or would it make the same sound if you stopped on a slight incline then let the car roll forward with the clutch still in?

FanTapstic!

Hi mate,
It only does it when I letting the clutch out. I did the test as you advised, it won't make the growling noise.

Does the diff not in the centre affect the stability, wear and tear of the car on the road mate?
Or is it a bit of a gimmick to make it look nice?
Stability wise, the car isn't bad at the moment.
I'm not too worried about driving locally with the noise mate. I've been doing it for past four years and long trips as well.
It didn't get any worse. My only worry is that the diff, gearbox or uni's suddenly giving away in the middle of nowhere.
Actually, it got slightly better after I repacked the front bearing, hub and the steering ball joints(bearings).
I have a feeling, when I put larger tyres on the back for few weeks, it wasn't making the grunting noise as much(or wasn't making it at all)
The ATs I have on it are 225/75R16, which comes to around 29 inch diameter. When I put the 31.5 inch muddies on rear wheels, it didn't make lot of grunting noise.
I'm just going to test it now with the muddies in the back again.
Thanks

[dom14]

It sounds like the normal 1000/1100 rev rattle that all TD42's have.
I believe it caused by the clutch plate springs rattling at that particular rev.

nothing to worry about but go test drive another one and compare if you really want to.

Yeah, I think so too mate. It's time to borrow a mate's GQ and drive around for a day or so.
I can't find any bloke anywhere near with an RB30 Patrol though. Plenty of TBs out there though. :)

[dom14]

I just changed the back wheels from 225/75R16(29 inch diameter) AT's to 31.5 inch muddies.
Then I did a test drive. It cuts the growling noise by half or more.
What does that mean guys?! Can you please help with that?
Thanks

[taslucas]

Hmm, hard to diagnose. Are you able to video the sound?

FanTapstic!

[dom14]

It's an rb30.

Dom, I wouldn't worry about the diff being slightly to one side. If you wanted you could fit an adjustable panhard rod to bring it back to centre, but I'm sure there are plenty of patrols about that are sitting the same as yours.
As for the rumble/grinding noise, does it do it only when letting the clutch out ti move forwards or would it make the same sound if you stopped on a slight incline then let the car roll forward with the clutch still in?

FanTapstic!

Hi mate, I just wanna make sure I understood your question. Did you mean I stop the car on a slight downhill (decline) or uphill(incline) then let the car roll forward while clutch is still pressed? I can let the car roll forward downhill(decline) without letting the clutch go, obviously. Uphill(incline) I would have to depress(let the clutch go) won't I, obviously? I think I was too quick to answer without understanding your question.
Cheers

[Big Red]

Ah OK sorry, didn't realise it was an RB30 disregard my post.

does it make that noise only when turning and starting off ... EG: when turning right at the lights.
if so it could be the wrong oil in the rear diff ... LS85/140 works fine but 85/90 can shudder.

could be the tyres, muddies can rumble at really low speed
uni joints can growl when they are worn

[dom14]

Hmm, hard to diagnose. Are you able to video the sound?

FanTapstic!

Yes mate. Just the camera is out of my hands at the moment. I'm hoping to do it this Friday.
Cheers

[dom14]

Hi Guys,
Please have a look at the photos. These photos might give a better picture about the car's wheels and suspension and what sort modifications it might have gone through.

Can you guys please tell me how many inches of lift this look like to have?

The wheels are 225/75 R16 ATs. Diameter comes as around 29 inch, which is pretty modest for a GQ Patrol, I reckon. They weren't my choice though. Came with the previous owner.
I reckon they might be too small for this GQ with it's suspension lift?!

Thanks