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[malcy_p]

[3.2 ex-police black manual saloon, 122k miles.]

Evening all

Typical - I'm back to work on Monday after a few weeks off over Christmas, and what happens today? Reversing out of the drive I get a slight rubbing/'chuch-chuch' noise from somewhere under the car. At first I though it was brake or handbrake related, but later pulling out of a t-junction (now going forwards...) I get a growling/knocking from underneath the car that sounds (for want of better words) like a baritone Wookie looking for a mate.  Ease off the throttle and the noise goes. Doesn't always come back under acceleration, and it doesn't appear to rise and fall with respect to road speed.

Could this be the prop bearing dying?

If so I've got a spare prop from a 3.0 manual estate, will this go straight on to a 3.2 manual saloon???

To swap the prop do the exhausts have to come off?

Or might it be something else altogether??

Thanks for any answers guys/gals.

/m.

[Entwood]

With my experience earlier in the year trying to diagnose similar odd noises .. and failing badly .. may I suggest the following as it was the only way I eventually found what was the problem.

Jack the rear of the car up as high as you can and place axle stands really well .. safety being paramount.

Use bottle jacks or similar under the shock absorber lower mounts to raise the wheels to as best as you can the "normal" position .. the idea being to get the wheels "back in line" not "dangling"

You can now run the engine and put the car in gear ... I was surprised that my auto very quickly ran through the gears and settled at just under 30 mph in top.

Providing you are happy with the axle stands .. now get underneath and examine the whole drive train whilst it is rotating .. ( this is why you want the wheels in the "normal" position relative to the diff .. it stops weird noises due to odd angles) ... you can even pull on the handbrake cables to stop each wheel in turn.

In my case this procedure very quickly proved that it was the diff that was making all the wrong noises .. one second hand diff later and all was fixed ..

HTH ...

[tunnie]

Does it have an LSD?

You mention pulling out of a T-Junction, does it only do with some steering lock?

Try booting it away in a straight line, then do same but as if you were turning right from a stand still

[Sir Tigger KC]

With my experience earlier in the year trying to diagnose similar odd noises .. and failing badly .. may I suggest the following as it was the only way I eventually found what was the problem.

Jack the rear of the car up as high as you can and place axle stands really well .. safety being paramount.

Use bottle jacks or similar under the shock absorber lower mounts to raise the wheels to as best as you can the "normal" position .. the idea being to get the wheels "back in line" not "dangling"

You can now run the engine and put the car in gear ... I was surprised that my auto very quickly ran through the gears and settled at just under 30 mph in top.

Providing you are happy with the axle stands .. now get underneath and examine the whole drive train whilst it is rotating .. ( this is why you want the wheels in the "normal" position relative to the diff .. it stops weird noises due to odd angles) ... you can even pull on the handbrake cables to stop each wheel in turn.

In my case this procedure very quickly proved that it was the diff that was making all the wrong noises .. one second hand diff later and all was fixed ..

HTH ...

  You're a lot braver than me Entwood!!! 

[Entwood]

 <snip>

  You're a lot braver than me Entwood!!! 

You have to have it that high, and get that far underneath to change the diff .. so little difference in actually running the engine under those circumstances .... but I did use 4 axle stands .. and the wheels were suitably placed as additional security .....

coward ?? me ?   Yup .. every time 

[Andy B]

......
coward ?? me ?   Yup .. every time 

A live coward is better than a dead hero      

[zirk]

Being Ex Plod, there's a good chance it will have LSD, my first thoughts would be alone the same lines as Tunnies thinking, Diff.

If you know its got LSD, is it still working as it should be with TC off?

[malcy_p]

You mention pulling out of a T-Junction, does it only do with some steering lock?

Try booting it away in a straight line, then do same but as if you were turning right from a stand still

Thanks for the replies guys. The noise happens in a straight line too. No LSD on the saloon, or if it has one it is very week. With TC off and one wheel on grass or mud that wheel spins up quickly. My estate has an LSD so I know how one feels! 

Any thoughts on swapping the 3.0 estate prop onto the 3.2? It might be the cheapest and quickest way to prove the bearing is at fault? If I had to change the front section would the whole thing need rebalancing? My quess is yes

/m.

[fiend61]

simple thing first have you checked diff oil level and condition, maybe some oil or a change might be useful 

[zirk]

You mention pulling out of a T-Junction, does it only do with some steering lock?

Try booting it away in a straight line, then do same but as if you were turning right from a stand still

Thanks for the replies guys. The noise happens in a straight line too. No LSD on the saloon, or if it has one it is very week. With TC off and one wheel on grass or mud that wheel spins up quickly. My estate has an LSD so I know how one feels! 

Any thoughts on swapping the 3.0 estate prop onto the 3.2? It might be the cheapest and quickest way to prove the bearing is at fault? If I had to change the front section would the whole thing need rebalancing? My quess is yes

/m.

If it did have LSD might be curable with the right oil in it, if its not too damaged. 

Yep, best way to check. 

[malcy_p]

If it did have LSD might be curable with the right oil in it, if its not too damaged. 

Yep, best way to check. 

LSD oil is different to 'normal' diff oil isn't it? I ask as I have  3 or 4 litres of gear oil left over from doing the diffs, txfer case and gearbox on my Mitzi 4x4...

[Mr Gav]

LSD oil is different to normal diff oil, GM use an additive for normal diff oil, I used Valvolene LSD diff oil in my Senator and it was fine.
The noise you describe could be a perished propshaft centre bearing carrier, the thin rubber usually wears through and is easy to see if it`s past it`s best or worn through.

[zirk]

If it did have LSD might be curable with the right oil in it, if its not too damaged. 

Yep, best way to check. 

LSD oil is different to 'normal' diff oil isn't it? I ask as I have  3 or 4 litres of gear oil left over from doing the diffs, txfer case and gearbox on my Mitzi 4x4...

My understanding is a good se90 will do but you will need the LSD additive as well, or you can buy LSD oil ready mixed.

Have a look at the Opie Oil section in Parts for sale and wanted.

[2woody]

being an ex-police car doesn't give it a good chance of being LSD - maybe only one in five did have.

the props are interchangeable as long as they're both V6 and both have the same sort of gearbox. The prop on the fun-free transmission is quite a bit shorter.

[zirk]

[quote  LSD - maybe only one in five did have.
[/quote]Had 8 explods so far, all have had LSD, guessing Ive just been lucky then.