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ewikran
Veteran
Date registered: Jan 2009
Location: Tromso, Norway
Vehicle(s): W463 1997 300DT
Posts: 256
| Chasing vibrations
I am irritated by a vibration/noise in the car and I have trouble finding the source.
It is present between 80-90km/h and are most pronounced at about 85km/h.
I am running normal tires with rims with offset 60-63mm.
The vibration/noise is present at the same road-speed with the TC in low or high, which would exclude the prop-shaft between the transmission and the TC.
I do feel a very slight vibration in the steering wheel but the vibration in the car it self is much more pronounced.
I feel a vibration in the TC shifter but it does not increase noticeable in the 80-90km/h range.
No additional vibration or pulsation when applying the brakes.
Front wheel bearings seems ok.
The following has been done:
- Wheel balanced and/or substituted with a completely different set of tyres/rims
- New TC mounts
- All new bushing in the front and aft suspension. If anything this made the vibration more pronounced.
- New tie-rod ends
- New steering link
- New wheel bearing on both sides on the rear axle
- Newly greased propellers shafts does not seem to change anything
Any suggestions what to try next?
I was thinking of removing the prop-shafts in turns to see if one of them are the source. Is this a recommended procedure? Can the car be safely driven with only one (fore or aft) prop-shaft installed? I suspect that the centre diff must be locked when trying this. |
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Brent
Expert
Date registered: Apr 2006
Location: SW Colorado USA
Vehicle(s): '13 Wolfsburg GTI
Posts: 1754
| RE: Chasing vibrations
I'm not sure about your logic regarding the center propshaft. The TC reduction occurs downstream of the center shaft. If it has never been replaced, the center shaft would be my first area of focus. |
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Inkblotz
Expert
Date registered: Apr 2006
Location: Georgia
Vehicle(s): 90 300GD "Thundering Turtle II", w/ 603A turbo
Posts: 3186
| Re: Chasing vibrations
Motor & transmission mounts OK? |
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MiN
Extreme Veteran
Date registered: May 2006
Location: Alpujarras, Spain
Vehicle(s): No cars, at all.
Posts: 555
| Re: Chasing vibrations
You didn't say whether you had physically checked the centre prop shaft. If not, you need to get under the car and get hold of it. It should move fore and aft but if there is any movement laterally/vertically at either end, then you need to take it off and replace the ends. |
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shochu
Extreme Veteran
Date registered: Jul 2006
Location: Jakarta, Indonesia
Vehicle(s): indonesian-assembled '97 G300
Posts: 452
| Re: Chasing vibrations
are you sure your G can go 80-90 kmh in low range? |
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ewikran
Veteran
Date registered: Jan 2009
Location: Tromso, Norway
Vehicle(s): W463 1997 300DT
Posts: 256
| Re: Chasing vibrations
One of the CV joints on the centre prop shaft has been replaced by the PO.
At the same road speed the rpm of the centre prop shaft would be 2.48 higher in low than in high gear (gearing 0.87/2.158)
My thought was that as the vibrations occur at the same road speed and the rpm of the centre prop shaft is quite different, the source could not be the centre prop shaft. I would think that the source is something that revolve at the same speed as the wheels regardless of gearing in the transmission or TC, thus my thought of the front and aft prop shafts.
I was not able to do 90km/h in low range, but was pushing 80 and felt the vibrations start but didn't want to go further as I was approaching the rev-limit.
The vibrations is also present with the transmission and the TC in neutral and engine idling when rolling down a long hill. I would think this exclude anything on the engine side of the TC (centre prop shaft, transmission, engine, engine mounts etc.)
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4x4abc
Date registered: Apr 2006
Location: La Paz, Baja California, Mexico
Vehicle(s): 02 G500
| Re: Chasing vibrations
remove front drive shaft first, lock center diff and try the same speed
if the vibrations are still present put front d/s back in and remove rear d/s
still present?
front axle? bad transfer case?
dunno |
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ewikran
Veteran
Date registered: Jan 2009
Location: Tromso, Norway
Vehicle(s): W463 1997 300DT
Posts: 256
| Re: Chasing vibrations
Thanks Harald, I understand that its no problem driving with only one drive shaft in place.
Any reason one should start with the front? That is the one which seems to be most hassle to remove/install. |
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4x4abc
Date registered: Apr 2006
Location: La Paz, Baja California, Mexico
Vehicle(s): 02 G500
| Re: Chasing vibrations
the front is always the first to go bad (mark the flanges with a punch before disassembly!) |
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Johann
Veteran
Date registered: May 2006
Location: Centurion, South Africa
Vehicle(s): 1999 LWB 290GDT 1981 SWB 240GD+ Cabrio 2015 G63
Posts: 259
| RE: Chasing vibrations
If vibrations are constant at certain speeds you can eliminate load(torque) related problems by coasting in neutral at the speed the vibration is present. If vibration is still present in neutral I doubt that your prop\drive shafts are the culprits. I'm not sure how solid this theory is but I'm sure the experts around here can advise.
Johann
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zimm
Elite Veteran
Date registered: Feb 2010
Location: pittsburgh
Vehicle(s): lx470, 76 fj40, 72fj40, 96 gelandewagen g320.
Posts: 788
| RE: Chasing vibrations
Brent - 10/8/2011 9:55 PM
I'm not sure about your logic regarding the center propshaft. The TC reduction occurs downstream of the center shaft. If it has never been replaced, the center shaft would be my first area of focus.
second.
but i didnt feel mine in the wheel and it was toast. |
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ewikran
Veteran
Date registered: Jan 2009
Location: Tromso, Norway
Vehicle(s): W463 1997 300DT
Posts: 256
| Re: Chasing vibrations
Will problems with the pro-shafts only present it self under load?
I was under the car tonight, but could not feel anything on the front and aft shafts. Forgot to check the centre shaft, but I am still of the opinion that it can not be involved.
Anyone that can confirm my assumption regarding the RPM of the centre shaft versus the road speed in high and low gear on the TC?
I did however find something that seemed odd. I had one of the rear wheels of ground and could turn the rear prop shaft around 10-15 degrees before I felt anything in the front shaft. Just before the front shaft started to turn with the aft one there was a metallic "bang" noise from the TC, as it was something loose inside that suddenly makes contact. I would believe that it is the gears, but it seems to be a lot of space between the gears towards the front prop haft. Should the prop shafts have different gear lash in the TC?
I have heard this before while breaking on the engine on a slight uphill when the transmission shifts down to 1. gear. |
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thanito
Veteran
Date registered: Aug 2009
Location: Greece
Vehicle(s): MB G400CDI, MB 300E-24, Mini Cooper S
Posts: 253
| Re: Chasing vibrations
ewikran - 10/13/2011 12:11 AM
Will problems with the pro-shafts only present it self under load?
I was under the car tonight, but could not feel anything on the front and aft shafts. Forgot to check the centre shaft, but I am still of the opinion that it can not be involved.
Anyone that can confirm my assumption regarding the RPM of the centre shaft versus the road speed in high and low gear on the TC?
I did however find something that seemed odd. I had one of the rear wheels of ground and could turn the rear prop shaft around 10-15 degrees before I felt anything in the front shaft. Just before the front shaft started to turn with the aft one there was a metallic "bang" noise from the TC, as it was something loose inside that suddenly makes contact. I would believe that it is the gears, but it seems to be a lot of space between the gears towards the front prop haft. Should the prop shafts have different gear lash in the TC?
I have heard this before while breaking on the engine on a slight uphill when the transmission shifts down to 1. gear.
I have the same issues as you my friend. This clunking noise is heard even with the wheels on the ground while playing with the rear shaft???
I also have the vibration thingy.. Yet still no clue what is causing it. |
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ewikran
Veteran
Date registered: Jan 2009
Location: Tromso, Norway
Vehicle(s): W463 1997 300DT
Posts: 256
| RE: Chasing vibrations
I have removed the front prop shaft as suggested, but have hit a snag. I can not see any way to remove the bolts from the front output flange on the TC. Am I missing something?
I sertantly can not drive around with these loose bolts. Are the whole flange to be removed by removing the centre bolt?
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Loki Laufeyjarson
Date registered: Apr 2006
Location: 66°N, 19°W
Vehicle(s):
| RE: Chasing vibrations
ewikran - 11/8/2011 6:21 PMI sertantly can not drive around with these loose bolts. Are the whole flange to be removed by removing the centre bolt?
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ewikran
Veteran
Date registered: Jan 2009
Location: Tromso, Norway
Vehicle(s): W463 1997 300DT
Posts: 256
| RE: Chasing vibrations
Thanks, Loki.
As I wasn't prepared for this so I don't have nay shims or washers available. I will have to go an buy some tomorrow.
Here are a video that shows the play in the front diff with both wheel on the ground.
http://s1210.photobucket.com/albums/cc416/ewikran/?action=view¤t=IMG_0029.mp4 |
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AlanMcR
Expert
Date registered: Apr 2006
Location: US, CA, Los Altos
Vehicle(s): G300DT E300DT 230SL
Posts: 3500
| RE: Chasing vibrations
You can just cut some short sections of 8mm hose to make the shims.
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4x4abc
Date registered: Apr 2006
Location: La Paz, Baja California, Mexico
Vehicle(s): 02 G500
| RE: Chasing vibrations
the play is normal (lash in spider gears) |
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Fernando BR
Date registered: Jan 2007
Location: Brasil
Vehicle(s): G500/05 300GE/91 300GD/80
| Re: Chasing vibrations
shochu - 10/9/2011 7:23 AM
are you sure your G can go 80-90 kmh in low range?
I think not , but if it could at 80 Km/h i will go hi range.
Edited by Fernando BR 11/9/2011 1:21 AM
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ewikran
Veteran
Date registered: Jan 2009
Location: Tromso, Norway
Vehicle(s): W463 1997 300DT
Posts: 256
| Re: Chasing vibrations
Fernando BR - 11/9/2011 7:18 AM
shochu - 10/9/2011 7:23 AM
are you sure your G can go 80-90 kmh in low range?
I think not , but if it could at 80 Km/h i will go hi range.
I can and have done it several times, but just for testing purposes as described above. For all normal purposes I off cause use hi range.
And if you don't believe me, you are more than welcome to come and see for your self ;-)
Edited by ewikran 11/9/2011 9:38 AM
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