Help needed - V-V-Vibration

[CRH]

I have an NL petrol manual that has a vibration which is more of a sound than a feeling.
It occurs under moderate to hard acceleration and between 90-115 kph.
Have had the tailshaft checked and it is OK although I never really thought this was the problem.
Has anyone heard of this sort of thing? Three mechanics have told me to live with it, that 4WDs with LT tyres are never going to be smooth but this drives me crazy.

[mrbitchi]

How good is your exhaust?

[pampaskat]

Hi CRH. I used to own a 2000 LWB 3.5 (it looked like the Aussie NL, but was a South African spec GLS with DOHC motor) that had a similar issue.

It generated a thrumming vibration at 80 km/h and (more loudly) in a band around 100 km/h. I swapped wheels and tyres with a mate to see if it helps (made no difference) and I had the propshaft balanced several times by different specialists. I even had a whole new rear propshaft made. Nothing helped, until I swapped rear propshafts with another Paj. Then mine was smooth as silk and the other one had the bad vibes! While experimenting I attached an unbalance mass to my propshaft and this made the vibes noticeably worse.

When I learned that the owner of this other car was planning to sell it, I made him an offer to buy his propshaft, which he accepted, but later the bugger dropped me and sold the car without letting me know;.

My theory is that something inside the cabin resonates at the rear propshaft rotation frequency. Only a minute unbalance is needed to exite this resonance.

Not all of these cars seen to be afflicted with this issue, but I have heard of the odd case.


I really do hope that you get yours sorted, because I know how maddeningly irritating the vibes are.

[CRH]

Hi pampaskat,

I have now removed the tailshaft and driven it in front wheel drive and the vibration is gone. (A tiny bit at 100kph, but barely noticable)

I have been suspecting an output shaft bearing or bush and this sort of confirms it, I hope.

Of course, it may just be gone because the tailshaft is out.

[Martin]

Vibration

THis may or may not help however besides my pajero I have a VR/VS holden wagon which i purchased 8yrs ago & it always had this vibration which felt as though it was coming from the drive shaft. I had several mechanics look at over the yrs however no one could find fault and basical said the same, live with it it won't cause any damage anyway after 300,000 odd ks the diff finally gave up and being an old car a motor engineer suggested that we get the whole rear end from a wreckers and oddly enough one became available with low ks and after replacing, no more vibration and the car is the smoothest its ever been so after some deduction it was probably in the diff as all the outer parts were retained.

[mr_grumble]

Mate, I'd bet my left one that it's wheel / tyre related.
Is obvious if the rim is dented but not so if its the tyre deforming. Also check to see if there's any play in the front wheel bearings.

I've been a victim of both Cheap tyres deforming and a loose passanger wheel bearing, both giving exactly the same vibration as what you've indicated.

[CRH]

Well Mr Grumble I hope you aren't too fond of that left one, because, as I said, when I remove the tailshaft, the vibration is gone.

[Boodles]

Boodles

My guess is flywheel - Pajeros have a "dual mass flywheel" - there were heaps of posts on the old Pajero site about this problem - Google "dual mass flywheels' & you will get the gen on what they are - basically 2 flywheels sandwiched together with a flexible middle (rubber?) - the flexible material "goes off" after a few years & then you get a vibration. Lot of people get it after they replace a clutch - no slip in new clutch highlights the vibration - you should replace the dual mass flywheel whenever you change the clutch they advise - but of course they cost an arm & a couple of legs - hence most hope for the best - hope this helps...

[6G74]

My guess is flywheel - Pajeros have a "dual mass flywheel" - there were heaps of posts on the old Pajero site about this problem - Google "dual mass flywheels' & you will get the gen on what they are - basically 2 flywheels sandwiched together with a flexible middle (rubber?) - the flexible material "goes off" after a few years & then you get a vibration. Lot of people get it after they replace a clutch - no slip in new clutch highlights the vibration - you should replace the dual mass flywheel whenever you change the clutch they advise - but of course they cost an arm & a couple of legs - hence most hope for the best - hope this helps...

This maybe possible in some, but only the 3.2 did pajeros have a dmf, all petrols, and previous diesels are solid mass.

[6G74]

My guess is flywheel - Pajeros have a "dual mass flywheel" - there were heaps of posts on the old Pajero site about this problem - Google "dual mass flywheels' & you will get the gen on what they are - basically 2 flywheels sandwiched together with a flexible middle (rubber?) - the flexible material "goes off" after a few years & then you get a vibration. Lot of people get it after they replace a clutch - no slip in new clutch highlights the vibration - you should replace the dual mass flywheel whenever you change the clutch they advise - but of course they cost an arm & a couple of legs - hence most hope for the best - hope this helps...

This maybe possible in some, but only the 3.2 did pajeros have a dmf, all petrols, and previous diesels are solid mass and removing a tailshaft wont effect your flywheel.

[CRH]

Yeah, doubt it could be the flywheel as it happens even in neutral, when engine is idling. I have been to Mitsubishi and the output shaft bush is part of the rear cover and is $249. Not cheap, but could have been more I suppose. While I was there I got a price for front rotors $295 each. The same part from a brake place - $88. Thanks for your loyalty Mitsubishi.

[keith h]

CRH

Is there an update on the vibration? I suspect my NL might have the same problem.
Unless my 4 wheels are balanced to absolute perfection, I get a vibration coming in from about 80 - 100kmh.

[Loco]

I have been to Mitsubishi and the output shaft bush is part of the rear cover and is $249. Not cheap, but could have been more I suppose.

I had these vibe problems, turned out to be a combo of things but all tailshaft related.
tailshaft "flexed" on a offroad obstacle, slight imbalance, fixed that, one uni was stiff, relaced that, then noticed movement on the output bush when moving the yoke on the shaft when rear not coneccted.
Like yourself I thought mitsi price was exorbant for a $25 bush, shouldn't have to buy the housing as well. Anyways no one aftermarkets that size bush, I did find however that the L300 bush is the same thickness ID and OD, just it's shorter, so guess what's been pressed into mine for 2 years now. Still havent got around to someone turning up a duplicate of the old one. Oh yeah I replaced the front yoke too since all those years had removed some of the case hardening on the old one (this replacement was genuine )

Another point, if you vehicles had up to 2" suspension lift it will cause binding on the two uni joints going in and out of phase with each other, Paj is only three link rear which doesn't like lots of offset in uni joints. a five link causes the same operating angles of both uni joints where the three link, one will be at angle and the other straight, so Paj is better left with the tailshaft running close to straight in line output to diff, I spaced my tranfer case down to overcome some of this issue.

[keith h]

Hi pampaskat,

I have now removed the tailshaft and driven it in front wheel drive and the vibration is gone. (A tiny bit at 100kph, but barely noticable)

:

How can it be driven with the tail shaft out? Doesn't the oil come out without the tail shaft yoke in place?

[Pajnh]

G'day Keith,

I used the old yoke seal & a 40mm Welsh plug,silastic around the inner & outer so of the seal so the welsh plug won't come out,
I found the same with the tailshaft out and drove it in 4h it was quieter and no Vibration,I have replaced both Unis & the bearing on the output shaft but since the tailshaft went back in the vibration is still there on sometime takeoffs & takeoffs mainly while turning,or when its in 4wd when we have been away Shooting,Yoke is ok but only runs the housing about 45mm to 50mm,,seems not quiet enough on the spline shaft,

Cheers;
Shane.

How can it be driven with the tail shaft out? Doesn't the oil come out without the tail shaft yoke in place?