My car has develop a problem but I am not sure if it's the transmission or else. Can some one help?

The car will jerk and there is a clunk noise every time when I shift to reverse and it will sometimes do the same when I shift to D

Also, when the car is running in 2nd gear and if I lift the throttle at the same time when it shifts to 3rd, the same jerk and clunk noise appear but it only happens between 2nd and 3rd gear

It will feel jerky (but no clunk noise) if the car is exiting a corner in 2nd gear at around 25mph while I give abit of throttle. If I want to prevent this jerking, I will need to feed the throttle extremely gently which is quite un-normal

Anyone has similar experience?

Thanks in advance

Sounds like your flexdisks. When they start to breakup you get clunking noises at the times you mention. Have them checked ASAP. If one breaks apart, you could be out a prop shaft or worse.

BTW, the flexdiscs should be inspected at every service. If you don't have a dealer or very good independent service your car, this is the sort of thing that breaks for neglect and winds up costing more in the long run.

It could also be an engine mount. Same symptoms. If you noticed a rough idle before it started clunking, motor mounts are even more likely.

If it's not a flexdisc or motor mount, it could be the tranny, but with a little luck it won't be.

You got an answer from someone who knows, but because cars (even W220s) have different transmissions and control devices for them, knowing what your are driving (year and model) would be helpful. This is also true of questions concerning other systems in your car. I don't get my mind reader certificate until next month.

Skylaw's right. Mileage on the car would be a big help in pinning it down too.

My educated guesses are based on putting over 300,000 miles on four S-class cars, but are just that. Take the car to a dealer ASAP because it will likely get more expensive soon.

Thanks guys,

My car is 2000 Nov S320 with around 50000 miles and my dealer can't find the root of the problem. This problem has been there for almost 13000 miles and it didn't get worsen, still pretty much the same as it happens at the first time

Regarding the flexdisc that you mentioned, is it inside the transmission or torque converter?

Any ideas?

Thanks again

The flexdiscs are the rubber joints at the front and rear attachment points of the prop shaft -- front at the output shaft of the transmission and rear at the differential. If the dealer can't find something as major as you describe this clunk, you should try another dealer.

Thanks whoover, i will double check this with the garage

Tell the dealer to read the DTB's, there are several updates for this exact problem, trans control unit, valve body, solenoid valves, and a couple of the spring discs inside the trans. All depends on what versions you have, the DTB's can pinpoint the cause.
The dealer just needs to put in a little effort.

Thanks for your suggestions. Hopefully they can find out what's wrong

Curious, if it's the spring discs inside the trans, will it be a very big job?

hi guys,

This afternoon. I got my garage to check the problem again by jacking it up with a driver in the car.

Then we got under the car and the driver swifted between R,N and D while we are under there to see where the clunk noise is. It turns out it is from the rear differential. My garage is suggesting the rear diff may need to be replaced. Any thoughts? The clunk noise is only happening when we shift it to R

Also, we discovered the cat. is busted too

Anyone know how much the rear diff and cat are?

How bad is the Clunk noise ???
There is going to be a noise in the diff when you go D-R because you are changeing the load surfaces on the crown wheel and pinion. But I would think any diff that badly worn would make all kinds of grinding noises when driving.
How was the input shaft, did the bearing have a lot of play??.
MB make pretty good diff's we dont have to change them very often for wear, unless they have leaked out all the oil. Be careful in diagnosis.
PM me with your vin and I will get a price of cats for you.

The pro. shaft has abit of play but the mechanic said it's within tolerance and the flexdiscs look to be in good shape. The clunk noise is quite bad especially if you are in the cabin and it will make abit of a jerk along with the clunk noise when I shift to R. We jacked up the car and went underneath it while having someone inside the car to shift. It sounded to me the clunk noise is similar to the noise when a metal hammer hit another metal surface. Strange is that the clunk noise isn't as loud as in the cabin.

They quoted me around US$2000 for the cat. replacement parts and labour. But for the diff., they are not sure yet as they haven't replaced any but they said to me it will be very expensive

hi guys

Finally the garage found out the root of this problem. It's actually relating to the torque converter. There is a bearing broke and they said I will need a new one. Does someone know how much is the torque converter?

thanks

So another bad news today.

So now my garage is able to fix the torque converter (they sent the thing to a specialist shop where can they unweld and open up the torque converter and they will replace a few broken bearings)

Then this shop told my garage that the problem inside the converter shouldn't cause the jerking and clunk noise while selecting R so my garage took out the rear diff and opened it up and have a look. it's turns out that the centre big major part is broken with a hole there so when we select R, the end of the axle will move inside this hole and the hole looks like it will be getting bigger and bigger if I continue to use the car. So now the conclusion is I need a new diff, completely new or refurnished by MB

As aleady stated, the diffs in these cars are very robust and problems are extremely rare.

I would shop around for a used diff with less than 100K miles since there is little risk that it will be broken or worn out.

Should not be expensive since nobody needs them so high supply & low demand = low price.