Vibration 2023 4M, Cali, 15k km

[JmStockholm]

Some observations:

(1) Look closely at "degree of blockage" from 36 to 55 seconds. I think you were on gear 7 - speed is quite steady (83...87 km/h) thus neither much acceleration nor deceleration. The "degree of blockage" is full time at 7.48% which means front and rear axles are maximally (for that speed) locked together - the same for both foot off the throttle and foot floored. Shouldn't be when throttle is eased off. Also should be at the maximum only when seriously accelerating.

(2) From 2:05 to 2:21 - gear 6, speed varies 80...86 km/h but "degree of blockage" stays at 0% - thus fully front wheel driven (see RED in my tables for 6th gear)

(3) From 2:22 till end - gear 7 - decelerating from 81 km/h downto 75 km/h but "degree of blockage" at 7.48% - thus keeping front and rear axles locked together (see ORANGE in my tables for 7th gear).

PS. The 98% "degree of blockage" seen on video is just a Haldex self-calibration spike. Haldex every now and then tests maximum pressure the pump produces - lasts just for a fraction of a second. Lucky to capture the moment.

Yes, I looking more carefully at your table I understand I need to do much more careful measurements. I also found the logging in obd11 so will try to get a proper measurement on a strech where I have stable vibrations as well. / Thanks alot for the pointers!

 

[JmStockholm]

Mainly just curious. On my case I suspected the sawtooth wear pattern appeared because the Haldex effectively locked front and rear axles thus I was driving a kind of front/rear diff-lock on.


Yes, the dash light will disappear when plugged in. However, the fault codes remain in memory..


Well, that's even better than removing the fuse.

Plug it in > Control units > All wheel Control > Live data > Tick the following

• Front left wheel speed
• Haldex clutch status

You should see degree of clutch engagement (percentage).

Just monitor the value at your vibration range - different gears - accelerating/decelerating - touching brakes.

You should see the percentage increasing when pressing harder, up to a certain point. And it should return back to zero when foot off the throttle.

Especially keep eye on that you get the zero during vibration when foot of the throttle.

You should NOT get the behaviour marked as orange or red below (percentage value not changing). The behaviour should be similar to as marked green throughout speed range.

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I think you can set up also a data recording in OBDeleven - under Charts (can't remember the details how-to but should be fairly obvious). Would be interested to see a log.

I logged a bunch of scenarios, but when uploaded them they where all named the same, so I can't distinguish one from another, well, well... Anyways, here is one that I know I logged first at 7:th in manual and when manually shifting down to 6:th gear Haldex Cluch get's down to 0 (and was then kept in 6:th until the end), and then varies as I accelerate or decellerate. I don't find the reconcilation it to the table as in the 70-90 km/h in 7:th gear the H-clutch i basically stuck ant 7.48% even when lifting of and letting the speed control take it down to around 70 km/h. In 6:th gear its much more responsive. I also carefully checked the vibration and it's independent of gear or throttle. At or aroudn 85 km/h it always vibrate in 5,6 or 7:th gear as well as uphill power mode or downhill coasting. And the vibration is always there but amplified on "wavy" road surfaces that induces the 11 Hz vibrations. At "non-wavy" roads it's still there but less pronounced. /Thanks!

 

[mmi]

first at 7:th in manual and when manually shifting down to 6:th gear Haldex Cluch get's down to 0 (and was then kept in 6:th until the end),

So obviously first 60 seconds at gear 7, and from 60 to 130 seconds at gear 6.

GEAR 6​

kept in 6:th until the end), and then varies as I accelerate or decellerate.

In 6:th gear its much more responsive.

Disagree here - when the degree of clutch engagement is plotted as a function of speed it's obvious the variation is because of the speed change - not because of acceleration/deceleration.

Thus based on the data:

no change of "degree of blockage" at all from speed 64 to 74 km/h - front and rear axles locked at max "blockage",​

and

no change from speed 80 to 91 km/h - fully disengaged 4Motion.​

GEAR 7​

in the 70-90 km/h in 7:th gear the H-clutch i basically stuck ant 7.48% even when lifting of and letting the speed control take it down to around 70 km/h.

Yes, exaclly - fully locked front and rear axles no matter accelerating or decelerating.

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At or aroudn 85 km/h it always vibrate in 5,6 or 7:th gear as well as uphill power mode or downhill coasting.

Ok, proves the Haldex engagement is not the cause for the vibration - as at around 85 km/h on 7th gear it's fully locked, and on 6th gear no engagement at all.