Haldex pump - how reliable?

[Acer]

Originally Posted by Rooster

I think the majority of the AWD's never actually get used and i don't think that helps,

Don't think what helps - the AWD? I am sure it helps a lot in slippery conditions and mud/snow. Not to mention towing.

[Tannaton]

Originally Posted by Acer

Don't think what helps - the AWD? I am sure it helps a lot in slippery conditions and mud/snow. Not to mention towing.

What he was saying is that very few AWD's are taken off road so the rear haldex is activated very infrequently - if at all - use it or lose it etc....

[Acer]

Originally Posted by Tannaton

What he was saying is that very few AWD's are taken off road so the rear haldex is activated very infrequently - if at all - use it or lose it etc....

Oh right, I misunderstood. Yes that could well be the case. I don't doubt that most people driving XC90s around UK roads will be in 2wd mode most of the time (that is assuming they even have the option of switching to 4wd, which is unlikely!).

Does anyone know if it is possible to damage the angle gear or worst still the main gearbox while trying to access and assess the spline sleeve?

[Rooster]

You won't do any damage getting to them altho angle gear can be a pain to get off the remaining splines at times,

I managed to remove and refit mine on drive at home on my XC90 when i changed engine altho a ramp makes life alot easier,

Depending on age of vehicle the spline sleeve can be a PITA to remove from gearbox if it needs changing which if the prop is free spinning with all wheels on floor it will do

[Acer]

Originally Posted by Rooster

You won't do any damage getting to them altho angle gear can be a pain to get off the remaining splines at times,

I managed to remove and refit mine on drive at home on my XC90 when i changed engine altho a ramp makes life alot easier,

Depending on age of vehicle the spline sleeve can be a PITA to remove from gearbox if it needs changing which if the prop is free spinning with all wheels on floor it will do

Yes I was just worried that if the spline sleeve is being stubborn they could bust the output shaft on the gear box trying to get it out.

[RoyMacDonald]

Originally Posted by Acer

Oh right, I misunderstood. Yes that could well be the case. I don't doubt that most people driving XC90s around UK roads will be in 2wd mode most of the time (that is assuming they even have the option of switching to 4wd, which is unlikely!).

Does anyone know if it is possible to damage the angle gear or worst still the main gearbox while trying to access and assess the spline sleeve?

Volvo have the Haldex unit outputting a small amount of power to the rear all the time. (for increased stability) Never any time when it isn't in use to some degree. Unless your splined sleeve fails that is on the pre 2006 cars.

[4candles]

Does anyone have a schematic of the system?
Don't want to use the word 'exploded diagram'! Doh!

[RoyMacDonald]

Originally Posted by 4candles

Does anyone have a schematic of the system?
Don't want to use the word 'exploded diagram'! Doh!

Here you are. One document is for Audi but it's exactly the same system.

[4candles]

Good man, and a fine Scottish moniker to boot...


I thnk my granny and your granny were both grannies, spooky.

[rambo]

My 138k 56 plate XC90 is making horrible noises from the rear when moving off and turning right and left at low speed
My indie service guy seems to think it is the Haldex unit as a general area to look.
This was replaced 2 years ago with a used unit and has run great until a month ago
I am loath to chuck more money at it without having some definite directional help.
The noise is a large bang which passes through the body of the car, either left hand or right hand turning at low speed
Any ideas please as this is spoiling what is an excellent vehicle ( except for this problem)?