'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