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M.B Spares
Date registered: Dec 1899
Location:
Vehicle(s):
| The case of the rattly gearbox.........
Hello from Australia, I run a workshop in Canberra Australia and have a huge drama with a 5 speed manual gearbox. In an effort to find a solution I have set about posting the details on all the G wagon forums around the world. Personally I drive a 1987 230GE SWB and are a member of the Australian Gelandewagen owners Association.
Chassis number: WDB460 333 27 05481 300GD LWB wagon
- Vehicle’s original specification was OM617 engine, naturally aspirated and 4 speed auto.
- Engine wore out and owner wanted more power as well as a manual transmission.
- Around the same time as the engine died, we purchased another 300GD with an aftermarket Turbo and 5 speed Getrag Manual gearbox (717 422), The body was very rusty as it was imported from the United Kingdom, but the engine had been recently fully overhauled.
- As deal was struck to fit this engine and manual transmission as well as carry out the modifications to convert from Auto to Manual.
- The work was carried and when the engine was started a rattle was heard coming from the gear box. Very quickly it was realised that this rattle must have been there when the engine/gearbox was fitted to the rusty 300GD. How this happened was that the rusty vehicle had a loose exhaust system and worn engine mounts so everything rattled masking the rattle coming from the gearbox.
- Diagnosis of the noise revealed that it would go away when the clutch pedal was pushed down. It was there in neutral and in all forward and reverse gears. The noise level did not change between gears.
- Gearbox was removed and the input shaft bearing was found to be very badly pitted. This bearing was replaced and the gearbox reinstalled, only to find the noise was exactly the same. Spend some time listening to the noise. Find that it will go away if you put it in gear (on the hoist, wheels hanging free) and very lightly apply the foot brake. Take you foot off and the noise comes straight back. So quite obviously some kind of free play in the gear sets.
- Gearbox was removed again and all roller bearings replaced including those in the sandwich plate. Gearbox was reinstalled with no improvement in the noise. Very frustrating.
- Priced new gearbox and nearly had a fit! Found a new 230GE gearbox (717 420) that we could buy for 1500Euro. Spent 2 hours looking at the parts books to see what the difference is. The only difference I could find was the bell housing. So ordered the 230GE gearbox and had it air freighted out from Germany.
- Very carefully removed the 230GE bell housing and fitted the 300GD bell housing, double checked all the clearances and installed the NEW gearbox and NEW throw out bearing. Same noise!
- Removed gearbox again and tried a new clutch plate, the old plate had done around 30000kms and appears to be perfect, reinstall gearbox, noise still there.
- Spend hours thinking about it and cruising the net. Find plenty of stuff but none like this. Listen to noise in gearbox. Remove the shifter plate and drain out 50% of the oil. Put a listening probe into the gearbox with the engine running. Do the trick of putting it in gear and then light pressure on the brakes. Find noise is at the loudest near the input shaft gear. So theory is that the noise is the input shaft gear rattling against the lay shaft gear. Theory is that the rattle is caused by the vibration of the 5 cylinder engine.
- Discuss problem with a MB tech who has worked on these for years. He says there is a MB service bulletin that recommends SAE30 engine oil. Replace shifter plate and fill with SAE30 engine oil, start engine and let clutch out. No noise, go for a drive, oil gets hot and the noise comes back.
- Vehicle drives perfectly, gear changes are OK (but a little stiff when cold with the SAE30 oil) and there are no other noises. When you drive the vehicle you never hear it. Pull up at some traffic lights and so long as you have your foot on the clutch no noise. Take you foot off the clutch and it starts.
- End result is 12 months work, lots of money that we will never recover as the job was done to a quote and an upset but somewhat sympathetic customer. Customer does not want to take delivery of the vehicle unless we can fix the noise.
- Many people tell me that these are all like this; I have trouble believing this as if they were MB would either never have sold one or had the most horrendous trouble with warranty claims. The noise is terrible, especially when the gearbox is hot and has the correct specification oil in it.
Some theories that we have come up with from brain storming it are:
- Engine out of balance, but it runs very smooth and produces good power.
- 300GD bell housing incorrectly machined so the two shafts are too far apart.
- Turbo back pressure on the exhaust system creates the imbalance.
Someone somewhere around the world must have had this problem before all I have to do is find that person? If say there were a set of bell housings that were machined incorrectly this problem will have happened before.
Any help very much appreciated.
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460332
Date registered: Apr 2006
Location: Europe
Vehicle(s):
| RE: The case of the rattly gearbox.........
Hi.
The noise/rattle problem you describe is WELL KNOWN and almost everyone leave it there, it causes no problem!
Here in Norway you find lots og G's, and most of the drivers and mechanics know about this problem. We call it plate/dishes rattling.
I've seen several repairs/operations as you describe, without any result. I have the problem myself, and as you state,
only when the engine/transmission is warm. I think your theory about engine out of balance is interesting since som
vehicles are known to have vibrations while driving - without the mechanics beeing able to find the source. My vehicle,
a 1984 SWB, all standard, no turbo, has both light vibrations around 70 km/h and the gearbox rattle.
I've heard several theories about this and I been thinking about these issues myself:
1. Bad master or slave clutch cylinder, throw out bearing might not fully retract and rattle.
2. Worn guide tube that the throw out bearing runs around. The guide tube should have som high-temp grease on.
3. Different type of clutch plate with different type of springs that come loose and rattle. What plates have you used?
4. There might be an issue with the light, medium or heavy duty throw out bearing. What do you use? The light is from plastic.
I see that you hoist the vehicle and use the brake, that would probably releate the problem to the gear axles?
Another way to diagnose the rattle is to lightly force the gear level from neutral and towards/into 1. gear, wheels on ground,
engine running, foot off the clutch. That should stop the rattle too? This test point towards the output axle or lay shaft from engine
vibration as well, don't you think?
A guy I know has a 1982 LWB 617A, it has like 4-500.000 km, I know his vehicle has absolutely NO rattle.
I will see if he knows what clutch plate he uses, if he know when changed? I've also seen many different type of slave clutch cylinders,
I don't know if you can mix 4-speed and 5-speed slave cylinders, the thick and thin seal seals and shorter or long axles, but not sure if
that could cause such problem?
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hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| RE: The case of the rattly gearbox.........
Very nice to hear from you John. I only wish it was under better circumstances. When talking about rattles and noises, as you know it's very difficult to say what's "normal" and what's not from thousands of miles away and I don't want to put you off your course with mis-placed advice. You surely know your business and have done a lot of the things I would have suggested already. Not to mention that you drive a G yourself and so you know what can be achieved.
For what it's worth, I drive a 1980 LWB G that I've converted to use a 617A turbodiesel engine (my engine is very high miles with badly un-balanced compression across the cylinders, but still runs okay and gets me around). I use the iron-box 5-speed overdrive transmisison with mine and I also have some noise that I can hear with the engine idling, trans in neutral, that goes away when I depress the clutch pedal. It's not at all what I'd call objectionable though, so I haven't gone anywhere near as far as you have. This noise has been constant for me across the roughly 80,000 km that I've put on this combination.
If you want to compare noises, maybe we could share sound files or something to compare.
I can't say that this is a solution, and it seems far-fetched, but since it relates to the diesel drive line with manual trans, I'll bring it up. 460 diesels with a manual trans had a big round weight sandwiched between the transfer case rear output flange and the rear drive shaft. I've never been able to speak directly with an MB engineer to find out the exact purpose of this part in this application, but clearly it can affect drive line vibrations and might have an affect on your rattle.....might make it worse too!
About the only other thing I can think of is something with the pilot bearing in the tail of the crankshaft that might be putting a funny load on the input shafts of the various transmissions you've tried. If you didn't renew it yet, it might be a good idea to do so, taking care to drive it straight and only apply pressure to the outer race when doing so, of course.
As long as I'm grasping at straws, I have to say that I just noticed your note that the engine you're using had been "recently overhauled". In my time on this list listening to and advising lots of people, as well as in general life experience, I have to say that I've seen many more cases where "recently overhauled" turned out to be a lot more of a BAD thing than a good one. And in my own experience rebuilding the MB OM617A, this engine is not one that's easy to do well without experience. Personally, I know exactly three people (counting myself) on the North American continent that I would trust to do such a job properly. I'm sure there are more, but my point is that there are plenty of mistakes to be made by one not familiar with the nuances of the engine.
You did mention turbo backpressure so I'll say that the standard 300GD exhaust doesn't work very well with the turbo. A 280GE exhaust works nicely and is the same size that the turbo engines used in the MB sedans. If you work out the flow numbers, the turbodiesel, with it's lower peak RPMs needs to flow about the same volume as a 280GE at full song (same reason a 3" raised air intake works well on both, but I digress). I even went so far as to try mine without the (standard 280GE) muffler and found it made no difference in performance or exhaust temperatures (I measure pre-turbo).
Feel free to contact of-list through the "send private message" feature if you'd like to exchange sound files.
All the best my friend,
-Dave G.
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460332
Date registered: Apr 2006
Location: Europe
Vehicle(s):
| RE: The case of the rattly gearbox.........
The round weight between the TC and the rear output flange is a vibration damper built just like the one in front of the engine.
But, can you find these on the LWB, in later productions (1985-86) Mercedes had them removed from the SWB too, manual transmission or not.
Here's some pics, show the rubber that bind the two metal hubs/parts together.
http://www.pointedthree.com/disc/forums/showthread.php?tid=14698
Could some oil leakage from the rear engine Borgmann seal relate to a worn crankshaft bearing too? If so, that might be my case for a few.
I know Mercedes (WIS) says the Borgmann seal will leak a bit when the engine is not running and the oil pressing from behind, therefore thay say; park uphill.
Sure the cross checking with other faults to the rattle problem has seldom been discussed before, could be a way to the solution.
Edited by 460332 6/22/2009 11:44 AM
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hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| RE: The case of the rattly gearbox.........
Thank you for that link! I had missed that part of the discussion. I have the damper for the rear driveshaft, and a shorter shaft that's correct for use with it on a LWB. I've just never fitted it because factory fitment looked like it required long bolts through the t-case flange before the flange is fitted to the case, so I was waiting to have the t-case out. I know I could try and find some high-strength long studs, or have some made, but I need to renew a t-case anyway so was going to fit the bolts then.
But from your post and another one following it there, it seems that I should try and get this damper fitted asap. I'll try and get it done when I change to the new engine soon.
Thanks again!
-Dave G. |
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460332
Date registered: Apr 2006
Location: Europe
Vehicle(s):
| RE: The case of the rattly gearbox.........
But will you have to mount that damper? Was it ever mounted on the LWB...?
I thought the short rear driveshaft on the SWB got a more narrow angle at the U-link and thus a greater change in angular velocity
that caused vibration. I can really cannot see why they later were able to remove the damper on the SWB?
They sell two different rear driveshafts for the SWB, 566 mm shaft for the v-damper and a 616 mm.
I know that in 1981 the 461 LWB did not use the the damper, nor did early SWB gasoline engines with manual transmission have them.. 
The bolts you need might be 460 990 52 01 (65 mm long, I think?), not sure!
A new damper (460 410 03 47) cost something like US$ 1700 from Germany... 
Edited by 460332 6/22/2009 7:12 PM
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Nazrat
Veteran
Date registered: Jun 2009
Location: Northern VA
Vehicle(s): 1994 G320 Europa Import for sale, 2003 G500
Posts: 200
| RE: The case of the rattly gearbox.........
Might it be the clutch disc itself rattling? Does anyone have a truck they can try without the clutch plate handy?
Here's my modified (bastardized?) 1980 300GD with a swapped-in Getrag 5-speed and 8-bolt rear driveshaft:
-Tad
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M.B Spares
Date registered: Dec 1899
Location:
Vehicle(s):
| RE: The case of the rattly gearbox.........
Hi guys, thanks for all the input. The donor vehicle for the mechanicals in this case was a SWB so no damper. But, as the damper is only really doing something at speed this is nothing to do with my problem.
What is interesting is that the noise is more or less the same at idle stationary and at idle with it in gear (as the wheels free on the hoist).
Yes an engine rebuild can be suspect, and I did not do this rebuild, but I have had the head off (to check) and it all looked good. It starts first time, idles very smooth and makes good power (for a OM617).
I have a 4 speed steel case transmission from a W123 and was thinking of fitting it up and seeing is the rattle was still there. |
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Inkblotz
Expert
Date registered: Apr 2006
Location: Georgia
Vehicle(s): 90 300GD "Thundering Turtle II", w/ 603A turbo
Posts: 3185
| Re: The case of the rattly gearbox.........
I had a similar issue with mine. It turned out to be the needle cage bearing (inside the transmission at the end of the input shaft) was worn out. I first had replaced the main bearing reinstalled the tranny similar noise then pulled the tranny again and replaced the needle cage bearing and all was good. Additionally I had replaced the throw out bearing as well so the combination of the 2 stopped the noise.
Mark |
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dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: The case of the rattly gearbox.........
Mine has the noise. I think it is the needle cage at the back end of the input shaft as Mr. Inkblotz describes. In your case it could be the front bearing too. That bearing has a two piece inner race that if it is not tight, it will get noisy because the shaft is working against the gears in different angles as torque is applied to it from the motor. It needs to be held straight in there with true solid bearings on either end of that shaft. If one of the bearings is worn it will be noisy at lower RPM's in neutral.
Does the noise spin out and become smooth as you increase the RPM's to around 1500 or so? Mine does this. It can rattle and be noisy at low RPM's but at some point as the motor spins up it will stop and become smooth and quiet. I am talking about when the transmission is in neutral and the clutch is engaged. With the clutch pedal in and disengaged it never makes the noise, ever. Again I have the stock overdrive Getrag 5 speed manual transmission.
It is possible that the throwout bearing is a cause of this irritation but I really doubt it with mine.
-Dai |
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Inkblotz
Expert
Date registered: Apr 2006
Location: Georgia
Vehicle(s): 90 300GD "Thundering Turtle II", w/ 603A turbo
Posts: 3185
| Re: The case of the rattly gearbox.........
In addition to Dai's comments regarding the tightness of the main bearing. There are shims of different thicknesses that are used achieve this tightness.
Mark |
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M.B Spares
Date registered: Dec 1899
Location:
Vehicle(s):
| RE: The case of the rattly gearbox.........
460332 said
"Another way to diagnose the rattle is to lightly force the gear level from neutral and towards/into 1. gear, wheels on ground,
engine running, foot off the clutch. That should stop the rattle too? This test point towards the output axle or lay shaft from engine
vibration as well, don't you think? "
So yesterday I did the push into gear with the clutch not depressed test, and yes the noise goes away. But having a look a the other box I have here that is assembled, but has no bell housing on it al that does is the same as putting the brakes on lightly when we had it on the hoist and in gear. It loads up the gears that spin on the layshaft and they in turn load up the lay shaft and then the input shaft, so no rattle.
dai and Inkblotz, the box that is in there now is a new box with a new (split race) bearing and all shimmed up to factory spec. So I doubt that is the issue. Have thought about various shimming ideas but all that will do is move the gears in and out. If we could get them a few thousands of an inch closer to each other may be they would not rattle. But there is no adjustment for that. One other thought that has been sent to be is that to some very small extent the gears sould grow when hot? So in theory they should get closer togeather and not rattle....... Very frustrated, are going to see if I can post a Youtube video on it to show you guys what is like.
Edited by M.B Spares 6/25/2009 7:35 PM
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hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| RE: The case of the rattly gearbox.........
460332 - 6/22/2009 5:08 PM
But will you have to mount that damper? Was it ever mounted on the LWB...?
I have to say I'm not certain. I think it was on some LWB because the LWB 300GD parts truck I got had a drive shaft that seems to be shorter than the one in my 280GE by about the length of the damper weight. Unfortunately the weight and t-case were already gone from that truck, so I don't know for certain until I check the EPC for its VIN. I got the weight separately from a good friend in the UK, just in case I'd need it. I'll try to remember to check EPC and report back for sure.
-Dave G. |
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460332
Date registered: Apr 2006
Location: Europe
Vehicle(s):
| RE: The case of the rattly gearbox.........
Remember to open the vibration damper, there is a big needle roller bearing inside (D=15 cm) that needs to be cleaned and greased! |
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petermerle
Expert
Date registered: Apr 2006
Location: Cape Town ( deep south )
Vehicle(s): W460 *1, W123 *2, W124
Posts: 1315
| RE: The case of the rattly gearbox.........
I don't think its vibration damper on rear Propshaft - as the rattle is present at idle , damper only works when turning. OM617 engine needs to be re-balanced when you change flywheel . When you rebuilt gearbox did all the clearances get set up properly? Also the rear nut on drive flange works itself loose if not properly tabbed.
Peter |
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dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: The case of the rattly gearbox.........
You guys are talking about a couple of different vibration dampers I think. The one at the rear of the t-case used in the 460 diesels that the rear driveshaft plugs into is a carefully machined steel part with a blob of rubber in it. I have checked mine for balance and it is perfect. Exactly in balance to a degree that shocked the balance shop. It has nothing to do with the transmission rattle when the gear selecter is in neutral and the clutch is engaged with the foot not touching the pedal.
-Dai |
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460332
Date registered: Apr 2006
Location: Europe
Vehicle(s):
| Re: The case of the rattly gearbox.........
The rear prop shaft vib.damper has nothing to do with the gearbox rattle but is mentioned as answer to a question in this thread.
So, there is still a 15 centimeter wide needle bearing in the rear prop. shaft vib. damper!
If you have one on your vehicle, open it, clean it and add new grease to the needle bearing!
And as Dai says it is fine balanced, I would keep the parts oriented as they was!
(I've already mixed/hijacked this thread with just mentioning the rear prop vib. damper, but too many add post without reading all
previous postings, this just make the threads over complexed.)
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Werner Wild
Member
Date registered: Dec 2011
Location: the Netherlands
Vehicle(s): w460, 300GD, manual 5 gearbox, short WB, '84
Posts: 17
| Re: The case of the rattly gearbox.........
@Author, did you solve the noise problem? Mine (300GD from 84') has exactly the same problem: noise in neutral when hot, when cold no noise. I'm wondering what you did to solve the problem. |
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dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: The case of the rattly gearbox.........
I have had this rattle in my five speed for over three years. It spins out when the idle is advanced to slightly above 1000 rpm. I do not let it rattle. It is not there when the clutch is disengaged (pedal in) and is only there at low rpm idle. I suspect it is the needle cage which I didn't change when I repaired my five speed with a modified one piece bearing (no split inner race). I have not taken the thing apart yet because of the time involved and the transmission works perfectly. It just rattles at idle.
I think that the needle cage might not fix it alone if the clearance on the input shaft or mating surfaces for that little needle cage bearing are not in spec. There may be wear in there because of the axial play in the input shaft due to the stock bearing wear. If that shaft is flexing it will load the little needle cage and those needle bearings are going to make new space. It may need to be sleeved to fully get the play out of that end of the input shaft. It is the logical source for the problem noise. All of the motor torque goes through there. It will amplify the pulsing of the motor and each of the five cylinder tiny explosions. My transmission has not behaved any differently and is fantastic except for the noise....
-Dai |
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petermerle
Expert
Date registered: Apr 2006
Location: Cape Town ( deep south )
Vehicle(s): W460 *1, W123 *2, W124
Posts: 1315
| Re: The case of the rattly gearbox.........
dai - 2/14/2012 8:44 AM and is only there at low rpm idle. -Dai DAi , I'm curious as how do you tell if its not there above low idle as engine noise will swamp any gearbox rattle sound. Mine does it as well - it only started doing this after fitting a new Clutch and release bearing Peter
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