'82 240d (manual trans) Grinding/Clunking on acceleration
 

I had an awful noise begin 2 drives ago in my 240d. I noticed a clunking/grinding noise only on higher rpm's in 1st gear.

It would make 3 clunking noises, then after I'd shift into second, it would stop until I'd get into higher RPM and then it would clunk/grind many more than 3 times. The sound was accompanied by intense vibrations.

I found after that drive that the air filter housing had broken off causing a horrible rattling, and I identified the noise with that.

After mending the air filter housing, I drove the car again today and the same clunking/grinding noises and vibrations were apparent, and began worsening.

The grinding in second gear became almost constant and more intense, causing the car to jolt back each time the sound occurred. It disappeared while accelerating and cruising in 3rd and 4th gear, but in lower rpm coming to a stop in 3rd gear it would ensue around the 25<x<30mph range.

It sounds like it's either coming from the rear end or more under the drivers seat at the driveshaft.

A friend of mine has suggested to me it sounds like the differential, but also told me to check my axles and driveshaft.

I replaced my passenger side rear axle earlier this year where it sounds like it may be coming from, but i think it's also noteworthy to mention the flex discs are cracked all to hell. I already have replacement discs and driveshaft support + support bearing, just haven't put them on yet because I've been so busy fixing other problems she has been throwing at me.

What does it sound like to you guys?

Nick its hard to tell without hearing the noise .Are you sure its from the rear part of the car. Do you get this noise standing on the drive with no movement of the car and just speeding the engine up .If yes i would take a look at the flywheel . But thinking about it if its on the move, and with gearchanging .Look at the rubber coupling on the drive shaft .This is like a round rubber dougnut with steel tubes vulcanised in to it ,they just break down when rubber is worn out .It gives you this clunking an gearchanges .

Could be flex disc failure - could be other things.

First step =>

Look under the car and check for obvious damage.

I'd look at motor and tranny mounts.

Probably the reason we see so little issues with the manual transmissions although everything eventually wears. This transmission is the same one that was placed behind many of Mercedes strong gas engines in the day I believe.

Anyways a good inspection of the driveline components etc is the first step. I of course am not sure what it is at this distance but suspect it may not be the transmission. This based on your description.

One thing for certain is I cannot see something inside the transmission causing vibrations to the extent of breaking the air cleaner loose. I also would not drive this car until I locate what is going on. If you drop the driveshaft for example you will not be happy.

Put them on the car.

What brand flex disc and carrier bearing do you have?

As was said put them on....unless they are a cheapo brand, in that case....don't....

Shifter and shifter rods could also need to be rebuilt, as well as the transmission mount...

Again....crawl under the car and look...

Could be axles too...

Stop driving the car till you can jack it up and check the Drive line front to rear.

I agree with Greg, if you have the parts, put them on.

Jack up the rear of the car and set it on Jack Stands, securely block the front wheels. Front and back side. rock the vehicle to see it if it is secure on the stands.

Place the trans in neutral and release the Parking brake.

Rotate the DL, wiggle it up and down checking front and rear Flex Disk and center Support Bearing/U-joint.

If you have the Annular rear axles, check to see if the 6 bolts at the Differential end are tight.

If you do remove the DL, mark the two halves before removing it.
I use some cheap white Finger Nail polish from the $ store.

I doubt it the Transmission but ya never know
Look at your Shifter Bushings on the Trans Levers and then under the Shifter. It is where the three rods connect.
The things can be totally gone. (Bushings)

I found some interesting deteriorated Flex Disks.

http://www.peachparts.com/shopforum/...-flex-disc.jpg

This one is rather severe, but could happen

http://www.peachparts.com/shopforum/members/balge-albums-230te.html

Attached Thumbnails
http://www.peachparts.com/shopforum/..._uyfguys_1.jpg http://www.peachparts.com/shopforum/..._uyfguys_2.jpg http://www.peachparts.com/shopforum/..._uyfguys_3.jpg
http://dieselgiant.com/300SDL_rear_tran01.jpg
or worse, can tear up the tunnel.
From this thread.

In severe case I read where it broke the rear of the trans case.


When ever you feel a vibration, different growling noise etc... stop and check them out.


Charlie


sent from my pos computer

Ahhh that foot air conditioning picture surfaces again!

That can be tigged back together....

Indeed almost everything can be fixed with tons of filler rod and snips of metal!

I agree, put the parts on and inspect everything.

Thank you for all the suggestions.

I just got enough time to jack the car up this morning and get under there.

The front flex disc failed completely and is broken in 3 pieces, almost exactly like that severe example you showed. So I imagine that noise was the interior of the transmission having a bad day...

My flex discs, center support + bearing are all genuine mercedes (I do my best to only order Lemforder or Genuine Mercedes). I'm going under to install them now. I have school in a few hours so I likely wont finish until tonight.

Is there anything I should do to check the health of my transmission besides take a look at it from the outside to assess damage? Or should I just replace the flex discs, center support + bearing, and take it for a slow ride to see if the noise persists?

Just fix those things then test again...

If they are that bad, you may have to also be replacing the centering bushings. I would imagine it tore at least one of those up....

http://www.benzworld.org/forums/atta...bad-resamp.jpg
Damaged Centering Sleeve - Maybe Okay, but Getting New One - Mercedes-Benz Forum

Damaged one...
http://i35.photobucket.com/albums/d1...veshaft_01.jpg
http://www.peachparts.com/shopforum/diesel-discussion/274226-driveshaft-centering-bushings-any-magic-removing-them.html

Wow, luckily I got one of those centering bushings when I placed my order for the flex discs and center support + bearing. Hopefully I only need to replace it on the side that has the completely failed disc.

I dropped the tranny mount to access the broken front flex disc and found the rubber tranny mount is also deteriorated extremely, and softer than a baby's bottom. Also have that replacement part luckily.

Im having one hell of a time trying to get either of the flex discs un-seized from the flanges..

Anybody got a tip?

I'm afraid the only way i know of is to use thin flat blade screw drivers.

Not the right tool for the right job at all (I'm ashamed to admit).

Make sure you kill the flex disc and not the yoke.

When fitting new flex discs apply a wafer thin layer of copper ease / anti-seize to help the next person who is going to be going this job (and if it is you you'll be very glad you did it!)

Cool, I got the little devils out of there with some persuasion and now have the driveshaft disassembled.

The old center support bearing in there sounds awful when spun, and the outer portion of the center support was completely broken off of the center that holds the bearing.

The center support bushings on either side look completely fine surprisingly, and the U-Joint has no play in it so it seems fine.

On go the new flex discs, center support, and bearing....

Is there some trick to get the new bearing onto the driveshaft?

After installing the bearing inside of the new support, I try to push it onto the shaft and end up pushing the support off of the bearing.

Beyond that, I can't even get the bearing past the notch on the end of the shaft that the circlip is supposed to sit under. It just keeps getting stuck and I don't want to damage the bearing by pushing on it too hard.

I can not visual the situation
so I am going to give generic advice..
really really clean the items going together... like 1000 grit sandpaper..check for burrs....
lightly oil the things going together..
consider slightly warming or cooling those items you need larger or smaller... or a combo of both if you can...
sometimes dry ice is actually used in serious situations.... and electric heat guns are very nice compared to having to use a torch...

Use a hammer and punch to carefully tap the inner section of the bearing in place like this =>

http://www.peachparts.com/shopforum/...t-bearing2.jpg

Don't forget the bearing shield caps

http://www.peachparts.com/shopforum/3496692-post814.html

(OK that's a W201 but it looks much like your W123)

Forgot to say DIY here =>

PeachPartsWiki: Driveshaft Support (carrier) Bearing Replacement

Use as wide a punch as you can fit there....and use brass or bronze if you have it...
you want to push it in ... not flare it... although the race is very hard...
If you have a clean pipe of the exact size....
put it down over the splines and it will be easy to press it in straight...

Alrighty, got the new bearing on with some hot + cold and a punch.

Now, do I need to grease the splines on the shaft before reinstalling?

When I replace/remove an old Disc, I spray it down good with Kroil (penetrating oil) and let it sit a bit.
Then use a pry bar to get them off. Never damaged a Yoke yet.

For the center Support bearing I have a piece of Exhaust tubing of proper size, place a large Socket over it and drive it on.


Charlie


sent from my pos computer

Yes you want to clean the splines....very good and then use about a table spoon of grease on the splines before reassembling....You also want to do this for the centering bearings that are on each end of the drive shaft.....Also don't forget the new boot to protect the grease from road gunk...

So I managed to put the transmission mount on the bracket the wrong way, and then one of the bolts on the underside of the mount, which I installed before realizing I installed it the wrong way, stripped and now I can't get the tranny mount out of the bracket.

Any ideas of what I should do?

Pictures might help for us who do not know what it looks like off hand.....
make them with good light...
and put a little pointer showing what you are referring for better faster help....
So the bolt stripped and thus will turn in the counterclockwise direction but does not back out ?

I included two pictures, one showing the position of the seized bolt from each side.

And yes, it will turn counter clockwise and clockwise, but without tightening or loosening at all.

In the first picture...
you seem to have good access to that part...
is that the nut ?
You need to learn to get closer to the subject on something like this...

Yeah that's the nut. I don't know how to get it out without damaging the mount though.

Ok... what you need is called a ' nut buster'....
hold on and I will find a picture of it..
probably made by K and B....

there are two styles ....

https://www.google.com/?gws_rd=ssl#q=nut+splitter+tool

Alternatively a mini-grinder with a little cutting disk might help if you can't get a nut splitter. As with all cutting disks you can slip whereas with a gripping pinching cutting type apparatus you are often in better control (!)

Take the bracket down to your local machine shop. You're probably going to need a new nut tig'ed onto the bracket anyway.

Alright. The transmission mount, upon closer inspection, is either not the correct part or was not made correctly. The center cylindrical metal bushing in it was too wide, so it would not fit properly into the crossmember. I put the old one back on for now until I can get the correct replacement...

New center support + bearing, boot, and flex discs are on and man, the car has never felt smoother. The horrible noise is gone, and now shifting is much quieter and smoother. The vibration that has always been felt and heard when putting the car into first has left, and I'm a happy camper.

Thanks for the help guys.