W210 Transmission noise/howl/...ghost?

[ro80rob]

Hello

I've searched high and low on this problem and I've not come across exactly the issue I have.

Car:- 2001 W210.035 E200 (not the K model) with 5 speed 722.602 auto Transmission

Mileage:- 108.000 miles

I've had this car for just over 1 year and done 10,000 miles in it. It is the nicest car I've had, and I'm rather choked that it's developed a fault. This is despite the car being very cheap (why I bought it).

The transmission howls/whales above about 20 miles an hour, especially when its cold. As the box warms up, the noise will virtually disappear, but can be just heard at around 60 MPH.
When I say, whales, I mean that it can change note (it has a couple of resonances which it can jump between), and the note is also speed dependant. Volume comes and goes from loud to almost inaudible. Its not a harsh sound.
This fault has developed over the past month and I've continued to use the car every day for work, as, despite the noise, the transmission and car performs perfectly.
There is also no unusual/additional noise from the engine/transmission if I rev it in Park or Neutral. In other words, I don't hear any pump noise from the autobox hydraulic pump.
I also ran the car from cold up and down the road whilst using the 'manual' selection on the lever (never done that before) and I get the same noises regardless of which gear I'm in (above 1st anyway). Also the noise persists under load or on over run.

Things I have done..

When I got the car, I changed the transmission fluid and filter and the centre prop bearing as that was making a racket on over-run.

Since the noise started, I've changed the diff oil (though I'm convinced the noise is coming from the transmission region) and the centre bearing and carrier (again). There are no transmission oil leaks (level is spot on) and the diff doesn't leak and had good (now new) oil in it.

Tomorrow, I'm having the transmission oil and filter changed again (genuine MB filter). I am also considering putting some of that Lubegard Platinum additive in as a friend who had a transmission issue on a BMW was given this to help it (not selecting reverse) by a local auto gearbox specialist and it pretty much cured his fault. I'm wondering if the new spurious filter I fitted 12 months ago has maybe failed/blocked up in some way and its a hydraulic noise I'm hearing as the pump tries to draw fluid through it.
Could it be one of the solenoid valves in the box sticking in some way?
I am clutching at straws.

So...

Anyone care to advise me on what to do/test/fix next?

That would be great.

Cheers... Rob.

 

[BlackC55]

Get a experienced mb tech to drive it.

 

[ro80rob]

Update

OK
Thought I would post an update after some months of perseverence with my transmission noise.

As I mentioned, I was to have the transmission oil changed again, with another new (genuine) filter, and the Platinum Lubegard added.

Almost immediately there was a significant improvement in that the majority of the noise went away, with some residual noise at around 27 MPH, that re-appeared between 55 and 60 MPH (i.e. around 2 x 27 MPH). This noise would completely disappear when the transmission was warmed through. I noted that after a 360 mile round trip to Reading and back, this noise too has been reduced to a slight and occaisional gear whine at 27 MPH when the transmission is thoroughly warm. I have no other noises or issues with the transmission (though if it did whine at 30 MPH instead of 27 MPH, I'd have been still bitterly complaining).
All in all, it's been a major success, and I have now completed 20,000 miles in the car after 2 years of ownership. BTW, it's just passed another MOT with only a remark, so I'm about to start year 3 of my ownership of this £250 gem.

Since I am content with the operation of the transmission, I am less so of the replacement prop shaft centre bearings. When I bought the car, it was clear that the centre bearing was noisy, so I sourced a Febi (bearing and carrier) one from euro and fitted that. All was serene again till around 12 months later, when once again I had noise from this bearing. This time I sourced a more expensive bearing and carrier (ebay) and fitted that. I now find that this has also become noisy after around 12 months of use.
I am now in possession of a third bearing and carrier bought as cheaply as possible from ebay. I toyed with the idea of buying a new, genuine bearing from Mercedes themselves (~£20 + VAT), but decided instead to buy a genuine SKF bearing of the correct size which cost less than £5 from ebay again. This time, I bought one with the metal shields, rather than the rubber seals of the two I have tried so far. I have done this as it is the style of the original Mercedes bearing, which ran fine for over 90,000 miles. I have pressed out the bearing in my new 'cheapo' carrier and pressed in my new SKF bearing in readiness to fit. Hopefully this will stop my annual bearing replacemet ritual, which would be nice.

BTW, I took the opportunity to fit two new Febi flexi-discs on each end of the prop shaft. They are now 12 months old and seem absolutely fine.

So. Since it's the 27th of December, I'll wish you all the best.

Cheers... Rob.

 

[rorf]

Transmission howl definitely due to wrong filter (or incorrectly fitted) and probably wrong type of transmission fluid - use only genuine Mercedes stuff.

Likewise do not cheap out on prop shaft parts - use Lemforder or Merc only - many horror stories of damage in this department:fail

Because you bought it cheap doesn't mean maintenance will be cheap

 

[wu56Shoozz]

^ RE: Transmission - Not Necessarily, could be low fluid in the box causing the bands to burn.. had this before on another car, new box was required.

 

[ro80rob]

Thanks for the replies. I'll fill in a couple of details I now have.

Prop bearing
I have checked back through my purchase history.
The 2nd and much more expensive prop bearing (still fitted) was a Lemforder.
I am rather disappointed in these bearings, whoever manufactuures them. The carrier is simple enough, and that part seems to be fine. It's the deep groove ball bearing that puzzles me. It's not like it's a newly developed piece of kit. We've had races like this for over a century. Why is it they can't make them well and cheaply?

Transmission
When I first had the transmission fluid and filter changed, I did use a filter and fluid from euro. I don't recall checking the fluid level before we first drained it though!
When I had it changed again, I used a genuine Merc filter, but stuck with the euro sourced fluid as it was to spec. I also took advice from a Mercedes technical specialist (who I know via an aquaintance) who agreed that transmission fluid would be fine.
Each time the level was checked, it was found correct, both cold and hot. It would also seem difficult to fit the filter incorrectly. In addition, my problems started almost 7000 miles after I first changed the transmission oil and filter. BTW, all the work is done at a mates garage who has a lot of experience changing these parts on Mercedes.
As I said, I added the Lubegard Platinum as well. This was on the advice of a local and well respected auto transmission repairer. He did warn me that the 722 transmissions do have a small but on the radar history of torque converter problems.
I also note that there are issues with the earlier version of this transmission (pre 2000?). Also that the bush bearing where the torque converter pushes into the box can be a problem.

Things out of my control include the 95,000 miles covered by the car before I got it. I also don't know how it was driven. It is the lowliest 2 litre model without the 'Kompressor', so it's not really going to stress the box (I guess). I certainly don't have a heavy right foot and the trip computer tells me that I am achieving around 32 MPG on average.

So. If all continues as it is now, I've got it for another 12 months of happy motoring.
To be fair, the car has been very cheap to maintain so far. The biggest failure has been the front suspension spring carrier top that collapsed due to corrosion. My mate (mentioned above) was not suprised as he had fixed quite a few over the years. He told me (quite rightly) as it turned out that the local Mercedes dealer would 'have one in stock' as it was a common failure, and sure enough they did. £20 + VAT, a borrowed special spring compressor (from the Merc specialist) some welding and Schultz coating later, I was back on the road. The only interesting thing of note by my mate was that it was the drivers side that had failed, and all the others he had done were passenger side. He checked the passenger side and found it to be fine.
The car is going in for it's annual service next week.

Cheers... Rob.