MQ mass damper

[murwullambah]

Anybody know much about the mass damper on the rear diff, it acts like an anchor off road, just wondering if it could be removed.

[NowForThe5th]

Always struck me as a strange thing to attach to the front of a diff, particularly by a company who should have more 4WD knowledge than most.

I think your question has been asked before and fairly sure the answer was no.

[jerrah]

I think your question has been asked before and fairly sure the answer was no.

I was under the impression that it could be unbolted but you' might get driveline vibration. You could theoretically unbolt it prior to offroading. None of the manual MQ's have it fitted.

[murwullambah]

I supose i could try taking it of and see if there any vibrations

[RHKTriton]

Dogs get castrated...and still live.

[Longranger1]

Dogs get castrated...and still live.

Love the analogy

[murwullambah]

Hi, I have removed the mass damper of my MQ Auto diff just as an experiment, seems no different as yet, any thoughts on this or anyone explain what it actually does before I put it back on.

[grox]

From looking at it can you get any idea how it works. I have had only a quick look at one and couldn't believe why you would put a reef anchor under a car. It would hang up on a stump or rock within 5 minutes on the farms out here. Getting a bit suss with other reports about vibration but then it's only on the exceed model I think so hmmm . Would love know why it's needed and its effectiveness. Any chance of a close up picture.

[RHKTriton]

When I first saw one of the dampers I thought it may have been fitted incorrectly. You'd think it would at least be mounted to be higher than the drive shaft.

M'wully, have you tried mounting it differently?

I'd think as long as its approximately in the region of the uni it should do its job.

[murwullambah]

Only took it off today and went for quick run, got up to 90 ish km\hr and didn't notice any difference, think I'll leave it off for a few days and see how it goes, I'll have to look how to post pics and put one up.

[grox]

This is a quote from Pajero club forum referring to Challenger which apparently has one members name cookie


" I work in dynamics and vibration engineering and it's what is also known as a tuned mass damper and is most definitely there for a reason.

It could just be for noise and vibration comfort levels or it could also be for longevity of bearings/gears in the diff, by reducing vibration levels. I suspect the later, and it was probably something picked up late in development and hence the slightly ad hoc nature.

Noticing any difference with or without through the seat of your pants would be quite difficult as the drivetrain is already quite isolated from the chassis through rubber mounts. You would really want to check the change in vibration levels on the diff with accelerometers.

There will be a natural frequency of some component in the driveline which causes an undesirable vibration and the mass damper is tuned to flatten the peak vibration response. If modifying the key thing is to keep the mass the same but the direction of stiffness of the mounting is also important.

The PA also has a big one mounted on the back of the transfer case so it may be to do with the prop shaft and uni joints ".

So maybe 2 reasons it's there for comfort with regards noise vibration etc or mechanical but why mount it so it sticks out under the car facing forwards . From a quick read from where I found the info most owners have smashed the bejesus out of them.

[RHKTriton]

It is REALLY bad engineering to put anything on the underside sticking out like that damper.

[murwullambah]

This is a quote from Pajero club forum referring to Challenger which apparently has one members name cookie


" I work in dynamics and vibration engineering and it's what is also known as a tuned mass damper and is most definitely there for a reason.

It could just be for noise and vibration comfort levels or it could also be for longevity of bearings/gears in the diff, by reducing vibration levels. I suspect the later, and it was probably something picked up late in development and hence the slightly ad hoc nature.

Noticing any difference with or without through the seat of your pants would be quite difficult as the drivetrain is already quite isolated from the chassis through rubber mounts. You would really want to check the change in vibration levels on the diff with accelerometers.

There will be a natural frequency of some component in the driveline which causes an undesirable vibration and the mass damper is tuned to flatten the peak vibration response. If modifying the key thing is to keep the mass the same but the direction of stiffness of the mounting is also important.

The PA also has a big one mounted on the back of the transfer case so it may be to do with the prop shaft and uni joints ".

So maybe 2 reasons it's there for comfort with regards noise vibration etc or mechanical but why mount it so it sticks out under the car facing forwards . From a quick read from where I found the info most owners have smashed the bejesus out of them.

Might have to put it back and live with it then.

[srb]

If were me I'd be throwing that dampener as far away as my arm would allow... And probably aimed in the direction of a possum.

[murwullambah]

Some interesting reading from The Pajero forum

https://www2.pajeroclub.com.au/forum/sh ... hp?t=35472

[jerrah]

As said many times before on this forum: The manual MQ's don't have them! Has to be something related to the automatic gearbox?

[RHKTriton]

Don't remember from when I looked, does the auto have two piece shaft and manual a single?

If the auto has multiple unis, the damper may be there to cancel out a resonance created by the combination.

A harmonic balancer type setup on the pinion shaft may have achieved the same result without having the diff dragging its nuts over the terrain.

[Tony]

Throw it away if using the vehicle off road. Throw it even further if carrying weight and have suspension upgrade as will do nothing. Is there for comfort reasons, will not do any harm removing it.

[RHKTriton]

The mounting points on the diff might be a good spot to mount a traction bar.

Anyone checked out if they're strong enough?

[bennypage]

Don't remember from when I looked, does the auto have two piece shaft and manual a single?

If the auto has multiple unis, the damper may be there to cancel out a resonance created by the combination.

A harmonic balancer type setup on the pinion shaft may have achieved the same result without having the diff dragging its nuts over the terrain.

Apparently its the other way around but I am unsure. As when I look under my auto MQ it appears to have a two piece.

[Taylor922]

I have heard that the Pajero has the same damper and has for awhile, most reports I have got is that they remove them and there are no issues. Unfortunately nothing has been confirmed. Also will it react different on a independent suspension compared to solid rear with leafs

[shawty950]

I have an MQ exceed...and removed it about 20,000ks ago...I have not noticed anything untoward...but then I do run 33 MT Deegans and notice a bit of vibration/oscillation at 100kph...is it the tyres or the mass dampener being removed?...so far no takeoff vibration but I have the tjm centre bearing drop and ultimate suspension(with Karrman diff drop and uca's..currently in middle of blue plating)

[Merts]

I've had mine removed since I had the rear locker fitted. No vibration or other issues.

[explorer.dave]

I would be very surprised if Mits put dampers on for NO reason, why would they go to the extra manufacturing cost, and the obvious stupidity of a plow, if, it makes little or no difference? You may not be noticing the difference, but I would bet some-thing is. Best advise I have read here is to remove it only when off-roading.

[Merts]

The manuals don't have one at all, so the only explanation is that there is some issue with the auto that doesn't occur with the manual. I figure that my vehicle has lifted suspension, different wheels, and a tail shaft spacer. The 'system' has been altered significantly from factory, so whatever the issue is with the factory setup, it may not even still exist.

Anyway, there is no way Mitsubishi would have added the damper unless it was to mitigate noticeable vibration, and there is now no vibration apparent.