Essell55mb

Don't know if anyone else has this ?

But at very low speeds when just coming to a stop, the car judders - looks around 1000rpm.

Other from this the car runs well.

I don't think it matters if it's in Comfort or Sport mode and it's tricky to reproduce but is disconcerting when it happens.

No fault codes present, new spark plugs fitted, no obvious air leaks looking at the visible hoses in the engine bay.

Reset throttle using star.

Any ideas ? Maybe it's a 'feature'.... or maybe it's a fault on mine.

2004 sl55, 60k miles

next2pool

Does it do that with your foot on or off the brake? Try shifting into neutral and see if it still happens. It almost sounds like your torque converter clutch is not disengaging.

Essell55mb

Next2pool, yes I agree it does almost sound like the tc cutting in and out.

To answer the question, this juddering is with no brake pressure. If you brake, you can't feel any judder.

I believe you can apply a temporary disable of the lock up clutch via star, I wonder if that would be the next thing to try ?

next2pool

I'm not sure if you can disable it with Star, but even the lightest brake pressure does the same. You may try to lightly apply the brakes but not enough to actually slow the car but enough to actuate the brake lights which then should disengage the clutch.

Essell55mb

That's a good idea, I shall try the light touch brake idea - hopefully will give me a clue if it's the tcc or something else. Thanks

ItalianJoe1

Have you had a transmission service done on time? These cars do odd things when the fluid gets old. I'd suggest a normal filter/fluid service, and possibly a conductor plate if there are any fault codes at all.

Essell55mb

So a quick update,

Difficult to tell for sure but it didn't seem activating the brake switch made a difference.

Interesting you should mention the fluid change, about 200 miles ago had the fluid changed, and it did seem I picked up on this problem just after.

Today - measured the level, using the correct procedure, star measuring temp etc ... and it's overfilled when measuring both at 25 and 80.C


Obviously I'm going back to the garage to get this corrected, but do you think an overfill would cause this problem ?

next2pool

Overfilling a trans can cause lots of problems. The fluid will aerate and totally change shift quality and possibly damage the unit if not corrected. I think you are on to the issue.

nordicsl

Sounds like a transmission fluid problem.

Essell55mb

So the transmission was over filled by 1.4 litres.

Even after draining this excess it made no difference to the problem. ( and surprising that such a gross over fill manifested no other apparent shift issues on this gearbox )

My only further progress is noting the problem is significantly worse during warm up, then once warm is difficult to identify - however on / 0ff throttle down a slight incline you can just feel when warm up ( but not noticeable unless you were looking for it )

The irony is this problem only presented itself after having a preventative gearbox flush !!

Essell55mb

So, slight progress on this issue. I don't believe it is gearbox related now, the reason being is out of gear N / P when playing with the throttle you can notice that the rpm doesn't drop smoothly it drops in steps, which is what I believe I'm feeling as the jerking.

If any kind members driving their sl55 / sl500 are stuck in traffic, would you mind trying something for me ?
In N rev the car to approx 1200-1500 rpm, then release the throttle completely. Does it drop down smoothly to idle speed or drop in steps, especially jerky around 1000rpm ?

Thanks !

desired_speeds

My 04 E55 did this when it was cold but went away completely when it warmed up (10 mins driving). It also had a slight judder shifting from 1-2 gear at light throttle. I did some research back then and believed it was a solenoid on the valve body. It wasn't expensive and I was going to replace it at my next trans service but I sold the car before it happened.

moretech

I tried that speed drop test 1800 rpm on down and my 2003 sl500 did not have any jerks in the drop. I hope that helps. It sure bugs me to get improper service from a repair shop. I hope they put in the correct fluid too.

moretech

Essell55mb

Thanks for trying that test more tech, tbh it's what I would expect - I can't really imagine it would have been jerky that way from new.

I do wonder with gearbox flush if most shops just replace what they took out rather than doing a full check, i.e. Getting the oil up to 80 c then measuring level. So any previous level errors will just remain that way.

Essell55mb

Interesting you had a similiar problem, and with mine too it is more pronounced when it's cold. Did you get any error codes with your problem ?

desired_speeds

I didn't get any error codes.

Essell55mb

SOLVED !

After numerous routes of investigation, just could not find any fault to explain the symptoms.

The only thing I had in the back of my mind is the car had been remapped previous to my ownership ......

So had the original mb firmware reflashed onto the ecu, and basically solved the issue 100%. The car drives significantly better in all conditions, so who knows what rubbish was in the previous map.

Was interesting I picked up on the judderring symptoms after the gearbox flush which was a complete red herring. It does show with these fringe conditions once you pick up on them, your OCD brain won't let them go !

Now to do some miles on these amazing cars. 😁😁😁

Heatwave

Essel:

"had the original mb firmware reflashed onto the ecu...."

How did you do that/have that done?

Essell55mb

I have a local indie with star and subscription that did it. You can't do it with the clone star systems since you need an active subscription to the mb data.