AWD Transmission: Transmission Whine

[timh30]

Hi,

Does anyone else suffer a slight transmission whine on the xc90 ?

On my wife's car it only occurs around 30-50mph (or at least it can only be heard at those speeds), the pitch increases with road speed not engine rpm, and only occurs under load (i.e. when coasting there is no noise).

As it is road speed related, I assume it can only be occurring from the gearbox output shaft onwards. I did replace the spline shaft a little while back from the gearbox to bevel gear, and didn't notice any problems with that (i.e. no observable play and rotated freely).

[timh30]

From lack of responses, do I take it that no-one else has this noise on their XC90 ?

[GJB]

Have you thought it maybe it's wheel bearing they do whine when they are going very hard to tell which one.

[timh30]

Thanks for your reply.

It had crossed my mind about a wheel bearing, but I thought that would normally be more noticeable when cornering ? I would say the noise is coming form the front rather than the rear, and probably the passenger side rather than drivers (although difficult to tell exactly). There is no noticeable play in the wheels either - although not sure whether that is as applicable a test with these sealed bearings?

[GJB]

Originally Posted by timh30

Thanks for your reply.

It had crossed my mind about a wheel bearing, but I thought that would normally be more noticeable when cornering ? I would say the noise is coming form the front rather than the rear, and probably the passenger side rather than drivers (although difficult to tell exactly). There is no noticeable play in the wheels either - although not sure whether that is as applicable a test with these sealed bearings?

When I had a rear bearing go sounded if it was coming from the front.
No play on wheel at all when a front bearing went.
Have now replaced three wheel bearings in total.

[400-ascona]

Front wheel bearing I had go was speed dependant noise, and no change when cornering. It did sound feel like it was coming from the gearbox area.

Rob.

[timh30]

Thanks Guys, I will investigate this further, but is there any reliable way to identify which wheel bearing may be at fault, otherwise sounds it may be a bit trial and error approach ?

[400-ascona]

I agonised for day's before going for it, but got lucky and did the correct one!

[mat123]

Mine does this, it happens between 40-50 mph then dissappears. If I sit at 45 I can hear noise, then I knock gearbox into manual and drop down a gear, the noise goes away, put it back into auto and noise comes back, Why?

Matt

[400-ascona]

Originally Posted by mat123

Mine does this, it happens between 40-50 mph then dissappears. If I sit at 45 I can hear noise, then I knock gearbox into manual and drop down a gear, the noise goes away, put it back into auto and noise comes back, Why?

Matt

Mine was speed specific (around 45mph, and there was another point higher up (conveniently forgot what speed.....). Not sure it changed between auto and manual tho. It did move speed wise as time went by. However the bearings felt smooth with no play. You could also feel it through the floor when you hit the resonant speeds.

Rob.