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Cause of vibe felt especially on transfer box gear lever? 300gd

Joined
Feb 12, 2011
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Location
Salt Rock, South Africa
#1
-My Gd300 still has a heavy vibe especially felt on 4x4 gear lever;
-It had disappeared with centre shaft removed;
-Mechanic insisted its propshaft;
-Then upon me driving 200kms to him to fetch my vehicle he says it could be
transfer box but he didn't have time to detect.

-I brought it back, balanced shaft, no luck;
-local mechanic Replaced engine and gearbox mounts with original ones (I had
engine mounts redone but it made engine vibe worse since rubber was too
hard);
-local mech says the transfer box is the source of the vibe and wants to send it
to a gearbox chap to check.
-Thing is I don't know if his gearbox chap knows anything about a g-wagon transfer case.

-Does anyone know of a reliable, honest and efficient mechanic in Durban that can find the cause and fix it even if it means a transfer box overhaul?

-I've had enough of my vehicle sitting at mechanics workshops without the main problem I have being fixed just because it's to hard for them to crack or they too busy with easier repairs on other vehicles.

:(
 

Alan

G-Wagen Club SA
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#2
Adheel,
It's difficult to diagnose but let me tell you an overhaul doesn't come cheap as many of the bearings are agents only. Maybe another option and possibly quicker and cheaper is to source another TC and try it out, Maybe someone has one lying around and will allow you to test before purchase.
 
Joined
Nov 26, 2012
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Durbanville, Cape Town, South Africa
#3
It is not the transfer box. if there is any play in any of the prop shafts there will be a vibration. The transfer box vibrates because of the worn or out of balance prop shafts. I have overhauled two transfer boxes in my life and one of them was unnecessary. I purely replaced the bearings because the customer wanted it. The second box I did (Doug Nels) was only because of some sand that came the box which altered the faces of the gearsets. This cause a grinding noise. This we realised after repacing all the bearings with the noise persisting. In the end I sold him a spare box I had. Most prop shaft shops have not the facilities to balance a G prop shaft as it has to be done at 5000 rpm. This is the speed that they are balanced at in the factory. Being a very heavy shaft (truck like) but spinning at much higher speed, you quickly feel an out of wack G shaft. Also the correct phasing of the shafts is important. Is it a long or short wheel base.
 

Andrew

G-Wagen Club SA
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#4
I agree with Henri. Dont touch the trasfer case. Grease all points on shafts then:

1. put transfer case in neutral and gearbox in 4th and rev through rev range with hand on trasfer case lever. Vibes? Remove middle propshaft and go to 4. No vibes go to 2.

2. Remove front propshaft, engage 4 High, drive car at all speeds. Put hand on trasfer case lever. Vibes? Go to 3. No vibes take front propshaft to 4.

3. Remove rear propshaft and go to 4.


4. Go to a superior propshop with 5000rpm capability. Go elsewhere if they say 1500 rpm is good enough. Make sure you have the G wagon offset angles for the universals at hand before committing to a propshop.
5. Replace propshaft in vehicle and retest.

You can make new shafts out of 312 Sprinter parts for the universals but look for a better slip joint that more closely resembles the G. Sorry cant remember what works. Once again make 100% sure of the phase angles and spin it 5k when balancing.
 
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#5
If you need to know how to check the phasing angles just ask. After you have checked you prop shafts and everything is ok with them you can look at the transfer box mounts if there is still some vibration. Again I need to know if it is a SWB or a LWB.
 
Joined
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Salt Rock, South Africa
#6
Thanks for the advice. Its a short wheel base.
Going to look around for a 5000 rpm propshaft place tomorrow.
Hope its just that.
I will appreciate any other tips. I have no idea about
Shaft angles on a G. I will try to look for any other g owners in my
Area that might know or lend a shaft to test out.
 

Andrew

G-Wagen Club SA
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#8
Ok. For a SWB the middle propshaft has 0 degrees offset between the universals. This means that the crosspieces are aligned with each other.

The rear propshaft is the same.

The front propshaft has the front and rear universals "misaligned" with each other by 78 degrees. If it is an original MB propshaft there will be two arrows on each side of the slip joint that marks this angle. I would check this first.
 

Pete460332

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#11
Have you replaced the rear gear box mount. HAve you raised the vehicle by any chance - this can change propshaft angles resulting in vibration. The 300GD should also have a vibration damper on the output of transfer box going to the rear. Not sure what the effect is if not there but could be another factor. Does vibration happen at certain speeds only , does it change with amount of engine power being delivered through drive train?
 
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#12
Hi
The Land Rover workshop that's been replacing my mounts sent my
G to a propshaft house then a gearbox and diff specialist. He found that the
Dog nut from the transfer case flange missing and shaft threads worn.
They sorted and refitted and say most of the vibe is gone
But shafts need to be balanced or one of them need to be
Lengthened.

Hope to have my G back in a proper driveable state soon.
 

Pete460332

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#13
Hi
He found that the
Dog nut from the transfer case flange missing and shaft threads worn.
.... need to be
Lengthened.
.
Could you please explain ?? Dog nut , the "threads on shaft " and why the shafts needs lengthening? Has you got a modified engine in you G?
 
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#14
Hi
I was told The nut that holds the flange Was missing. About
The shaft Its possible thats not the original or correct one as
The vehicle was purchased with the vibration. Will explain
The correct story once I see the mechanic and speak to him myself.
 
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#15
Its clear that these people although trying to sort the vibration, don't know about GDs. When I tell them that the vehicle should be driven while up in the air on trestles they look at me as if I am stupid. My next move is to bring my G back to my workplace and try to work on it myself with the guidance of forum friends of course.

They say that the transfer box was too cramped up in the front and the slid it back along the "slot" and had the rear shaft shortened and front shaft lengthened.
All without asking permission and it hasn't helped the vibration.

Now they sent the vehicle to Propshaft Rebuilders to assess. I hear from another x 300gd owner that they are good and upon inquiry say they can balance to 4500 rpm but 2 things worry me:

1. The fact that the propshafts were modified may interfere or worsen the vibration. Can someone give me the correct propshaft lenghts and angles?

2. I asked these chaps if the G has a vibration damper and they say No.
do all 300gds have vibration dampers? In which case if its missing does anyone have one lying around that I could buy? And also what are the dimensions of the damper? (So I can figure if it was removed and shaft possibly extended?)

Thanks
 

Pete460332

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#16
The slot I presume is the amount of movement in the transfer cae backets - can't be more that 12 mm or so - no need to shorten / lengthen the propshafts.

all 5 cylinder 300GD came with vibration dampers - on the output of transfer case to the rear - I don't believe it is essential but I guess will give a slightly better damping of engine vibrations. MAny guys have fitted 300GD motors to a W460 chassis without the damper without complaining - so don't get carried away with that .
If you want to measure angles make sure that the driveline from crankshaft to rear proshaft is all in a straight line +- 1deg
So if you have an accurate inclinometer the rocker cover ( parallel to crankshaft ) , short prop shaft, rear prop shaft are all at the same angle and the transfer case flanges are all at 90 deg to this inclination ( only need to measure one flange as obviously all three and parallel to each other. You can also measure the rear axle flange with respect to the transfer case - these should be parallel
Measurements on my SWB 300GD as follows vehicle empty and on ground

Rear propshaft
Driven flange at transfer box 7.1 deg from vertical
Rear axle flange 7.4 deg from vertical

Center propshaft
Driven flange ( gearbox ) 6.2 deg from vertical - can measure this rocker cover in the horizontal result is just shifted by 90deg
Received flange ( at transfer box 7.1 deg

Front shaft
driven flange at transfer box 7.1 deg
received flange at axle 10.45 deg

Hope this helps











I
 

460LeoG

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#19
all 5 cylinder 300GD came with vibration dampers - on the output of transfer case to the rear - I don't believe it is essential but I guess will give a slightly better damping of engine vibrations. MAny guys have fitted 300GD motors to a W460 chassis without the damper without complaining


I

No vibes on mine with conversion without damper... Sounds like a proper headache... Hope the balancing sorts it.
 
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#20
Hi
I have fetched my GD300 from Propshaft Rebuilders and I am
Pleased to note that there is quite an improvement.
About 75% of the vibration is gone.
Chap says he had to remove and balance a few times
and used the off set info Pete supplied and advise from
an owner of a Merc scrapyard together with all info from threads
on vibrations that I found on the forum and faxed him to achieve this.

I notice it doesn't have a vibration damper and I think my
next move is to locate one and fit it but considering the improvement
maybe I will just not interfere and just run it as is for a while.

Just need to fix a leak on the t/box and change ignition etc

Thanks very much to all forum members that assisted.