Gearbox Problem

[steveyt]

Hi All,

I have a '98 E280 Elegance and it's developed serious gearbox problems. I had EXACTLY the same problem back in February with all the symptons EXACTLY the same. The problem was solved by changing the gearbox oil/filter/sump gasket. Now, a lot less than 10,000 miles later...

At the beginning of last week I lost all drive to the wheels and was left crawling across a roundabout with the engine revving uselessly. The first sympton to happen was a loud, high pitched whirring noise that raised or lowered in pitch in relation to the engine revs. Next it became a bit sluggish to engage gears and then rather than changing gear smoothly, the revs would flare between gears. Finally I was left being unable to select gears.

I have finally got round to having a look at what was going on today (working and the Silverstone Classic were priorities...). I have measured the level using the correct measuring tool from MB and adjusted the level of oil (it was slightly over the max mark and was fine in colour) so that the oil reads about 1/2 way between the minimum and maximum marks on the tool for the 2 markings for when the car is fully warmed up. I also took the measurement while the engine was running. When we first started it up the whirring noise was still there but disappeared after a short while, making me think that it just took a little time to work the oil round. The car was engaging the gears (could feel the slight twitch in the car and the lowering of revs) ok.

I left the car for 10-15minutes and returned to it later to give it a run on the road. When I started it up the whirring was there again. While I retrieved the measuring tool the noise went away! The levels were ok as before. I then tried to move the car and it would engage the gears but there was no drive to the wheels! I switched off the car and left it for 30 seconds or so then started it again. The noise had returned but it allowed me to pull it back onto the drive.

Sorry for such a long post but I've tried to put in as much detail about the problem as I can. Any help would be gratefully received

Thanks in anticipation,
SteveyT

 

[Dieselman]

At a guess it's either the pump or torque converter. It could be worth checking the filter and pipe are clear as a blockage to the pump will starve it of oil and cause a high pitched screech.

 

[BlackC55]

Drop the sump pan down and look for metal......

 

[steveyt]

Thanks for the quick replies. The filter blockage was suggested last time as a possible culprit, this would have been cured (temporarily it seems now) by the changing of the filter.

I have read about a magnet that was placed in the later transitions that will attract the metal particles that could contaminate the oil. If I was to get one of these and place it in the sump pan, along with a new filter, could this help? However, when we changed the oil etc. Last time, there was no metal particles or anything apart from oil in the sump.

 

[c240yaz]

Thanks for the quick replies. The filter blockage was suggested last time as a possible culprit, this would have been cured (temporarily it seems now) by the changing of the filter.

I have read about a magnet that was placed in the later transitions that will attract the metal particles that could contaminate the oil. If I was to get one of these and place it in the sump pan, along with a new filter, could this help? However, when we changed the oil etc. Last time, there was no metal particles or anything apart from oil in the sump.

If metal present, the damage has already been done, so a bit late for the magnet.

First port of call is as others suggest, sump off, check for metal shavings. More likely a torque convertor break up than the box ?

 

[armitphi]

my SLK ... doesn't have a drain plug so how is drained or indeed filled ... my gearbox sump seal leaked out some of oil took it garage but local garage ... they stopped the leak but couldn't top it up so now I have very odd gear changes ... lol and kickdown not as effective ...sorry to hijack this thread ... but gearbox ppl seem to be looking and I cant see an obvious way to start a new thread

 

[Dieselman]

my SLK ... doesn't have a drain plug so how is drained or indeed filled ...

I take it you are talking about an auto box in which case they all have a drain plug. Refilling is via the dipstick tube.

 

[c240yaz]

my SLK ... doesn't have a drain plug so how is drained or indeed filled ... my gearbox sump seal leaked out some of oil took it garage but local garage ... they stopped the leak but couldn't top it up so now I have very odd gear changes ... lol and kickdown not as effective ...sorry to hijack this thread ... but gearbox ppl seem to be looking and I cant see an obvious way to start a new thread

They obviously have no MB experiece.

There is a drain plug and as Dieselman says, it is filled via the dipstick.

Not surprised that your kickdown is not working. Lack of oil in the pan ?

You need to take your car to another garage, promptly.

 

[armitphi]

thanks guys ... once again I apologise for hijacking this thread
Phil

 

[steveyt]

No worries about the hijacking, at least it's another problem solved

At a guess it's either the pump or torque converter. It could be worth checking the filter and pipe are clear as a blockage to the pump will starve it of oil and cause a high pitched screech.

In regards to this, which pipes am I looking for? I am looking at WIS and I can see the Oil Filler Pipe (which isn't blocked due to the levels moving up when I put more in!) and the Oil Cooling Lines. Should I be looking for blockages in the cooling lines? Just reading up on flushing those lines and it says to use Kerosene................

Otherwise, is there anywhere I've missed when it comes to pipes going to/from the gearbox?

Thanks!
-SteveyT.