Monaro rear end noises

[VinceM]

Not of the decent sounding variety either from the exhaust. Car is an 04 Monaro VXR.

Firstly, at speeds of around 10mph or so and in a straight line, there is a rumble and slight wobble from the back of the car, whether it is cold or warm. It disappears as soon as I turn a corner. Since my work place has a site speed limit of 10mph this is noticeable every day, and has been getting worse. I suspect the diff is on its way out but would like some further reassurance that maybe it's not...

Also, and perhaps unrelated to the above, there is a knocking noise from the rear passenger side of the car when travelling at around 30mph over bumps (so generally around town driving). The set up at the back is the Monkfish rear end pac with pedders rear shocks and standard springs. THe bushes were done last year and the shocks were done a couple of months ago, although this noise was present before the shocks were changed, it just seems louder (ie I need to turn the stereo up louder to get rid of it). I'm not sure if this is connected with the above issue or not. Oh and the driveshafts have a little play in them although nothing untoward (or normal for a Monaro!).

Any help/advice appreciated - I'm thinking it might be new diff time but could do without that expense!.

[vxr2010]

If you are thinking diff then a fluid change with friction modifier would be first thing to do , it is an easy job to do , the front noise do you have the front road response pack too ? If so a had the arb bushes go a bit dry I used spray grease and it went away , noises can be difficult to track down

[Aitch 'H']

From the rumble at low speeds it sounds like it could be a wheel bearing, I would have thought a diff would whine rather than rumble so it might be worth checking if you haven't had them done with the other work you say you've had done

[VinceM]

vxr2010 said:

If you are thinking diff then a fluid change with friction modifier would be first thing to do , it is an easy job to do , the front noise do you have the front road response pack too ? If so a had the arb bushes go a bit dry I used spray grease and it went away , noises can be difficult to track down

The diff oil has been changed recently to the RP stuff. The other noise is also from the back.

I'm going out in the car in a minute so will see what's what.

H I thought the wheel bearing would be more noticeable at speed?

[jameshsv]

I hope nothing to serious vince

[VinceM]

jameshsv said:

I hope nothing to serious vince

Cheers, so do I!

It doesn't make the noise when the clutch is pressed down...

[Aitch 'H']

It's difficult to guess without hearing it, but if it goes away when you press the clutch down then it's going away when you take the load off so could it be something as simple as the UJ on the prop shaft?

[vxr2010]

If it's a bearing it is normally a drone , the drone can change on a corner , if you jack the car up and wobble wheels it's easy to find a knackered one , and there not too bad to change , and bearing and cir clip are not too much

[vxkev]

Check the propshaft centre bearing rubber is not perished mine had similar noises and the centre mount was bugred

[VinceM]

vxkev said:

Check the propshaft centre bearing rubber is not perished mine had similar noises and the centre mount was bugred

Probably going to see Neil at some point about this, but out of curiosity how do you check this?

[jameshsv]

VinceM said:

Probably going to see Neil at some point about this, but out of curiosity how do you check this?

Up on the ramp and easy to tell if centre prop bearing fked m8

[vxkev]

jameshsv said:

Up on the ramp and easy to tell if centre prop bearing fked m8

Yup ramp or stands it will be easy to see if the rubber is knackered move it up and down and sid to side if not obvious then you can see if the rubber is torn

[jameshsv]

Any news on this vince

[VinceM]

jameshsv said:

Any news on this vince

Not yet, no change though. Will hopefully be seeing Neil next week.

[VinceM]

Getting rather frustrating now.... I've had a new prop centre bearing installed as well as new (to me) driveshafts and the problem is better, but now I've also got a humming coming from the back at around 30-35mph all the way up to motorway speed - reduces slightly when the clutch is depressed but still there. The knocking noise is also still there albeit it has reduced since the shafts were fitted. Today when I went out at lunchtime I also noticed that there is a whine from the car (not sure of exact location) at very slow speed that disappeared when the clutch was depressed.

So over the weekend I'm going to:

1. Swap wheels front to back and see if that changes anything
2. Swap rear shocks left to right and see if that changes anything
3. Check tyres for any damage
4. Remove rear seats, trim etc just to be sure that nothing has worked loose

Is there anything else that I can do - my feeling is the diff is on its way out, so a nice big bill looms, which I'm less than happy about. If anyone can think of anything else it could be or what can easily be done via DIY please let me know. Could the knackered driveshafts have been masking the real issue with the diff?

[Yertis]

I had these symptoms and thought it was the diff, but it was actually the bearing delaminating – the hardened shiny surface breaking away from the body of the bearing. Changing the bearing easy, provided you have a particular tool (IIRC for the retaining circlip – I got MF to do it).


What am doing here? I haven't owned a Monaro for weeks...

[VinceM]

Thanks, but had the bearing done this week...

[jameshsv]

VinceM said:

Getting rather frustrating now.... I've had a new prop centre bearing installed as well as new (to me) driveshafts and the problem is better, but now I've also got a humming coming from the back at around 30-35mph all the way up to motorway speed - reduces slightly when the clutch is depressed but still there. The knocking noise is also still there albeit it has reduced since the shafts were fitted. Today when I went out at lunchtime I also noticed that there is a whine from the car (not sure of exact location) at very slow speed that disappeared when the clutch was depressed.

So over the weekend I'm going to:

1. Swap wheels front to back and see if that changes anything
2. Swap rear shocks left to right and see if that changes anything
3. Check tyres for any damage
4. Remove rear seats, trim etc just to be sure that nothing has worked loose

Is there anything else that I can do - my feeling is the diff is on its way out, so a nice big bill looms, which I'm less than happy about. If anyone can think of anything else it could be or what can easily be done via DIY please let me know. Could the knackered driveshafts have been masking the real issue with the diff?

1234 doing those things i cannot see anything coming of it !

[VinceM]

jameshsv said:

1234 doing those things i cannot see anything coming of it !

Neither can I but at least it eliminates then!

[vxkev]

Have you got any decent axle stands if so jack it up and put it on them nice and firmly, start car put it in gear and listen to see if noise is there, if so leave it running and in gear and get down under car and listen be VERY CAREFUL though not to get in the way of moving parts, that way it should be easier to locate the noise.