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[sticka_v8_init]

Hiya fellas,

Looking at buying another Mig due to mine being torn a new "a hole" by the MOT guy on Tuesday. The one i'm looking at has a noise described as "Large whine from the rear axle which i believe may be a wheel bearing that needs replacing."

Question is, by jacking up each rear wheel, can i tell if its the bearing or the diff   

Any advice appreciated as always 

Cheers

[Entwood]

Hiya fellas,

Looking at buying another Mig due to mine being torn a new "a hole" by the MOT guy on Tuesday. The one i'm looking at has a noise described as "Large whine from the rear axle which i believe may be a wheel bearing that needs replacing."

Question is, by jacking up each rear wheel, can i tell if its the bearing or the diff   

Any advice appreciated as always 

Cheers

To check the diff .. jack the car up so BOTH wheels are off the ground then insert decent axle stands. Then jack BOTH wheels up using the bottom end of the shock absorber .. I used a bottle jack for this .. easier to get in .. until the wheels are in the "right" place in the wheel well.. the idea is to get the drive shaft in the correct alignment as they drop as the car is jacked.

Once in position you can run the engine and drop it in gear .. on my auto it went to 30 mph in top very nicely as there is no load.

It is now possible to get under the car safely and listen to each bearing and the diff. you can pull on the handbrake cable each side and stop each wheel in turn.

On mine it was VERY apparent that it was the diff and NOT the bearings !! Replacement diff was not that hard to change with the car jacked high ..

[sticka_v8_init]

Many thanks for that.

Just to be clear, rear of car sits on axle stands. Do BOTH wheels then need to be jacked at the same time?

If only one wheel is jacked whilst the rear is lifted and then put in gear is it possible to misdiagnose ?

[Entwood]

Many thanks for that.

Just to be clear, rear of car sits on axle stands. Do BOTH wheels then need to be jacked at the same time?

If only one wheel is jacked whilst the rear is lifted and then put in gear is it possible to misdiagnose ?

IMHO ... it might .. the change of angle of the drive shaft on the "unjacked" wheel is a lot .. and would, I think, do two things .... stress the joints, and induce another possible noise as the UJ's are at a weird angle.

That was why I did it the way I did ...... as near to the "normal" driving angles as I could get it... if that makes any sense !!

[sticka_v8_init]

Many thanks for that.

Just to be clear, rear of car sits on axle stands. Do BOTH wheels then need to be jacked at the same time?

If only one wheel is jacked whilst the rear is lifted and then put in gear is it possible to misdiagnose ?

IMHO ... it might .. the change of angle of the drive shaft on the "unjacked" wheel is a lot .. and would, I think, do two things .... stress the joints, and induce another possible noise as the UJ's are at a weird angle.

That was why I did it the way I did ...... as near to the "normal" driving angles as I could get it... if that makes any sense !!

That makes perfect sense now. Many thanks for the advice, much appreciated. 

[sticka_v8_init]

Just had another thought....if it is the diff that's shot, are the diffs the same for a 2.5 manual and a 2.5 auto ?  If they are the same, then roughly how long would it take to swap diffs over ?

Keep looking at this motor, mine's goosed and need something soon.

http://www.ebay.co.uk/itm/Vauxhall-Omega-limited-edtion-Tourer-Estate-with-option-7-conversion-7-seats-/330820101729?pt=Automobiles_UK&hash=item4d066a2661

[Bionic]

I was told by a testing station (not my usual one) that the rear wheel bearings were both shot so I took it home and had a go myself. After a bit of reading I found out that the noise could also be caused by a limited slip diff being fitted and that, when I had taken it to my usual test station who knew the car well, confirmed that that was the case. An easy mistake to be made by testers who do not fully know the specs of every car they test and being testers they believe that they are all knowledable to the point of never being wrong anyway.
Hope that helps you............

[Entwood]

Just had another thought....if it is the diff that's shot, are the diffs the same for a 2.5 manual and a 2.5 auto ?  If they are the same, then roughly how long would it take to swap diffs over ?

Keep looking at this motor, mine's goosed and need something soon.

http://www.ebay.co.uk/itm/Vauxhall-Omega-limited-edtion-Tourer-Estate-with-option-7-conversion-7-seats-/330820101729?pt=Automobiles_UK&hash=item4d066a2661

I can't advise if the diffs are the same .. but changing a diff is not that hard. It took me about an hour and a half to get the old one off .. on my own (tip : don't try and catch a falling diff one handed... you won't and when your hand gets caught between the diff and the ground it hurts !!) with help from Rob and Chris the replacement would have gone on in less than an hour .. if the bolts had been the same .. but that's another story !!  3.0 diff fits a 3.2 EXCEPT for the difference in the mounting bolts .....   

[sticka_v8_init]

Just had another thought....if it is the diff that's shot, are the diffs the same for a 2.5 manual and a 2.5 auto ?  If they are the same, then roughly how long would it take to swap diffs over ?

Keep looking at this motor, mine's goosed and need something soon.

http://www.ebay.co.uk/itm/Vauxhall-Omega-limited-edtion-Tourer-Estate-with-option-7-conversion-7-seats-/330820101729?pt=Automobiles_UK&hash=item4d066a2661

I can't advise if the diffs are the same .. but changing a diff is not that hard. It took me about an hour and a half to get the old one off .. on my own (tip : don't try and catch a falling diff one handed... you won't and when your hand gets caught between the diff and the ground it hurts !!)  with help from Rob and Chris the replacement would have gone on in less than an hour .. if the bolts had been the same .. but that's another story !!  3.0 diff fits a 3.2 EXCEPT for the difference in the mounting bolts .....   

Thanks for that Entwood, gave me a chuckle. Reckon it's best to stear clear of this car i'm looking at. Found 2 others which are 2.6 CDX estate auto's on a Y and 03 plate respectively, for not a bank busting amount of cash extra to what the original one might go for. Both sub £1000  

Cheers again for the advice fella 

[RobG]

are the diffs the same for a 2.5 manual and a 2.5 auto ?

Nope.
Manual: 3.90:1

Auto:    4.22:1