Bananas
17th December 2023, 06:05 PM
Hello
I recently became the owner of a 2011 D4 2.7 which is creeping up on 340k. It has been owned since new by my parents who have looked after it very well. It has been their adventure rig for the past 10 years. The body interior and exterior are in immaculate condition considering the age and mileage. Parked next to a new one the only major difference you notice at 10 paces is the shape. I have no idea how they have kept it looking so fresh.
But with close to 340 on the clock it's not without it's noises. I'm working through issues and deciding where the comfortable intersection between mechanical perfection and budget exists. Expectation vs reality.
In the 2 months or whatever I've had it so far I've replaced the heater matrix and solved a clunk up front. The heater matrix was almost 100% blocked with radiator stop leak and the clunk was a sway bar bush. These were the main noticeable faults. Now I fear it's on to the more difficult to diagnose and potentially more costly ones. I have already done a fair few k's on it and I enjoy driving it very much.
There are 5 things on the nice to solve list (so far):
1: Slight shudder when cruising up a hill and the car shifts down - I suspect torque converter;
2: Harsh shifting - not so harsh that would make a non mechanically minded passenger comment or even notice, but not silky smooth either - perhaps a fluid change will heal it - perhaps something more;
3: Backlash in drive train - mainly a bit of a clunk when powering back on after coasting;
4: A noticeable vibration that kicks in at just under 120 km/h. Drop back to 115 and it's gone.
5: Some vocal angry bees or cicadas somewhere.
And it's #5 I'm fixated on understanding now and this is the one I'm hoping for some guidance on where to focus my suspicions.
The symptoms I have noticed are these:
At about 60 km/h up to about 120 when #4 kicks in, a pulsing hum begins. The hum is a bit like a swarm of bees but it pulses like cicadas - perhaps pulsing 3 to 4 times a second continuously.
It is only noticeable on very smooth tarmac.
It's there with the power on or off.
It seems to grow louder as speed increases.
I think the rate of pulsing stays roughly the same at all speeds.
It disappears on a sweeping left bend and returns when approaching straight ahead and it remains on a sweeping right bend.
It becomes less noticeable almost to the point where I'm tempted to say it disappears when powering up a highway hill for example this one:
"The Mt Ousley hill is about 50km south of the greater Sydney metro area and runs down the scarp to Wollongong. For the high volume of transport companies running freight between the two cities, it's the only way down. The average gradient is 9.6 per cent and the maximum, near the bottom is a dangerous 25.7 per cent."
It is louder on the bottom of a dip when you are heaviest in your seat and becomes quieter when bouncing over a rise.
It seems to be more biased on the drivers side - but I have not been in the passenger seat to compare.
It is kind of like tyre noise but less slappy if that makes sense, more reminiscent of a background noise familiar in sci fi films: Waow-waow-waow....
So, what do you think I should suspect first and how would I go about narrowing down the suspects? Is there another way than simply pouring $$ into transmission components 1 by 1 till it's gone? Should I accept it's part and parcel given the mileage?
The easy fix is turning the music up but even then the low frequency waow-waow-waow creeps through when I hit a smooth section.
I recently became the owner of a 2011 D4 2.7 which is creeping up on 340k. It has been owned since new by my parents who have looked after it very well. It has been their adventure rig for the past 10 years. The body interior and exterior are in immaculate condition considering the age and mileage. Parked next to a new one the only major difference you notice at 10 paces is the shape. I have no idea how they have kept it looking so fresh.
But with close to 340 on the clock it's not without it's noises. I'm working through issues and deciding where the comfortable intersection between mechanical perfection and budget exists. Expectation vs reality.
In the 2 months or whatever I've had it so far I've replaced the heater matrix and solved a clunk up front. The heater matrix was almost 100% blocked with radiator stop leak and the clunk was a sway bar bush. These were the main noticeable faults. Now I fear it's on to the more difficult to diagnose and potentially more costly ones. I have already done a fair few k's on it and I enjoy driving it very much.
There are 5 things on the nice to solve list (so far):
1: Slight shudder when cruising up a hill and the car shifts down - I suspect torque converter;
2: Harsh shifting - not so harsh that would make a non mechanically minded passenger comment or even notice, but not silky smooth either - perhaps a fluid change will heal it - perhaps something more;
3: Backlash in drive train - mainly a bit of a clunk when powering back on after coasting;
4: A noticeable vibration that kicks in at just under 120 km/h. Drop back to 115 and it's gone.
5: Some vocal angry bees or cicadas somewhere.
And it's #5 I'm fixated on understanding now and this is the one I'm hoping for some guidance on where to focus my suspicions.
The symptoms I have noticed are these:
At about 60 km/h up to about 120 when #4 kicks in, a pulsing hum begins. The hum is a bit like a swarm of bees but it pulses like cicadas - perhaps pulsing 3 to 4 times a second continuously.
It is only noticeable on very smooth tarmac.
It's there with the power on or off.
It seems to grow louder as speed increases.
I think the rate of pulsing stays roughly the same at all speeds.
It disappears on a sweeping left bend and returns when approaching straight ahead and it remains on a sweeping right bend.
It becomes less noticeable almost to the point where I'm tempted to say it disappears when powering up a highway hill for example this one:
"The Mt Ousley hill is about 50km south of the greater Sydney metro area and runs down the scarp to Wollongong. For the high volume of transport companies running freight between the two cities, it's the only way down. The average gradient is 9.6 per cent and the maximum, near the bottom is a dangerous 25.7 per cent."
It is louder on the bottom of a dip when you are heaviest in your seat and becomes quieter when bouncing over a rise.
It seems to be more biased on the drivers side - but I have not been in the passenger seat to compare.
It is kind of like tyre noise but less slappy if that makes sense, more reminiscent of a background noise familiar in sci fi films: Waow-waow-waow....
So, what do you think I should suspect first and how would I go about narrowing down the suspects? Is there another way than simply pouring $$ into transmission components 1 by 1 till it's gone? Should I accept it's part and parcel given the mileage?
The easy fix is turning the music up but even then the low frequency waow-waow-waow creeps through when I hit a smooth section.