"Hoot" noise from auto trans.

[AUSSIE-X5]

Hi fellow Xers,
Just hoping that one of you may have had this problem with your X. When I accelerate (mostly up any incline) I get this "hoot" noise as it changes gear with an associated vibration from the auto transmission. Before you ask, I've checked and there is no 'owl' living under my X5. I,ve got an 05 diesel which I'm told is the same auto on the 4.4 V8 (in Oz anyway). The BMW service guys say it's more a sofware update problem and they are waiting for the new update to arrive, but it sounds and feels more mechanical to me. Any ideas?

[Heli]

I'm in Melbourne, too, and have a noise issue on shifting: details in this thread.

Not quite the same, but PM me and we'll compare notes

[AUSSIE-X5]

If anyone is interested, the BMW tech puts the noise down to the "Lifetime Oil" being too thick and causing hydrolic hammering when shifting. Sounds fair to me but we'll see after the tranny has been flushed and replaced with new "Lifetime Oil".

[mogsyman]

I have had this problem in both my 3.0d and current 4.8is.

Felt a bit of a prat when I mentioned it with the 3.0d as I got nothing but blank looks from the stealer service guys, but now the 4.8 does it! The 4.8 is due a service shortly so I'll mention the 'lifetime oil' answer.

[chris_barry]

I havent looked under the X5 diesel, but my past cars were Saab turbos and they had a hooter valve. This was actually what the service guys called them. It is simply a turbo blowoff valve, like what the boy racers have, except it vents back into the inlet tracts so you only hear a muffled hoot.

Get the 3.0d on boost and lift suddenly. If it hoots its just the blowoff valve operating. On the SAAB's they have an uprated version of it that didnt hoot. The uprated version was a bosch motorsport version.

Chris

[mogsyman]

Originally Posted by chris_barry

I havent looked under the X5 diesel, but my past cars were Saab turbos and they had a hooter valve. This was actually what the service guys called them. It is simply a turbo blowoff valve, like what the boy racers have, except it vents back into the inlet tracts so you only hear a muffled hoot.

Get the 3.0d on boost and lift suddenly. If it hoots its just the blowoff valve operating. On the SAAB's they have an uprated version of it that didnt hoot. The uprated version was a bosch motorsport version.

Chris

That wouldn't explain why it also happens in my 4.8 petrol though

[mogsyman]

Originally Posted by chris_barry

I havent looked under the X5 diesel, but my past cars were Saab turbos and they had a hooter valve. This was actually what the service guys called them. It is simply a turbo blowoff valve, like what the boy racers have, except it vents back into the inlet tracts so you only hear a muffled hoot.

Get the 3.0d on boost and lift suddenly. If it hoots its just the blowoff valve operating. On the SAAB's they have an uprated version of it that didnt hoot. The uprated version was a bosch motorsport version.

Chris

That wouldn't explain why it also happens in my 4.8 petrol though

[AUSSIE-X5]

Originally Posted by chris_barry

I havent looked under the X5 diesel, but my past cars were Saab turbos and they had a hooter valve. This was actually what the service guys called them. It is simply a turbo blowoff valve, like what the boy racers have, except it vents back into the inlet tracts so you only hear a muffled hoot.

Get the 3.0d on boost and lift suddenly. If it hoots its just the blowoff valve operating. On the SAAB's they have an uprated version of it that didnt hoot. The uprated version was a bosch motorsport version.

Chris

Won't be the blow off valve because the engine is under power. I know the sound your talking about, this is different and not as cool.