My 1999 E55 occassionally has a problem on 1-2 upshift under full throttle. The car feels like it stumbles. I believe what is happening is that the engine hits the rev limiter before 2nd is fully engaged. It seems to happen more often in cold weather. The dealer has not been able to reproduce the problem. Somebody told me there is a service bulliten covering clutch pack replacement on 1999 and 2000 E55s. Can anybody help?

There is a modified ECU for trans, # is 026-545-75-32/26; only this version will help.

What is an ECU? Has this problem been fixed on the 2001 model?

I have driven both the 2000 and the 2001 E55 extensively, I find that in both cars, if you step on the gas really hard and then partially let go (often the case when the car is picking up too much speed too quickly), the car kind of stumbles trying its best to smooth out the 1-2 shift.

I find that if I floor it and keep my foot down all the way, I get perfectly clean upshifts.

Let me know if you have further questions.

I am absolutely positively sure I have the problem I posted when I hold my foot to the floor. The tachometer indicates it exceeds red line (also there appears to be some tach lag which v and definately needle bounce when this happens).

Listen to DOC, the ECU (Electronic Control Unit) is reponsible for ALL of the shift requirements. That is harshness and timing. This tranny is 100% electronic.

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Benzmac:
Donnie Drummonds
300E
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM
OWNER OF MB AUTOWERKS .COM

Regarding the transmission, I'm just curious if it is bad for it if I manually downshift slowing the car to a complete stop? The owner's manual does not recommend us doing this during the break-in period and I'm just wondering why.

I'll appreciate any experts enlightening me on this one!

Benzmac:

First, on Tuesday Nov 7 the car goes to the dealer along with a printed copy of the response from M.B.Doc was kind enough to post. I hope this fixes the problem. But, at the risk of sounding like I am biting the hand that feeds me, I take issue with your statement that the tranny is 100% electronic. The controls are electronic, but the insides of the tranny are a complex mechanical/fluidics system. A knowledgable friend owns a 288 Ferarri GTO which is maintained by a retired Mercedes technician. According to my friend, this guy was called in by Mercedes USA to help debug shifting problems (I don't yet know specifics but have an inquiry in to this guy) on 1999 E55s. The result, my friend claims, was an updated clutch pack which is documented in a service bulliten applicable to 1999 & 2000 models. I can imagine that the transmission fluid viscosity when the transmission is not fully warmed up, coupled with a cold ambient air which might make the motor produce just a little more power, would collectively add up to slightly faster run-up and slightly slower transmission lockup during the 1-2 upshift which would cause this problem. Even if this was the problem, I could also accept that a different ECU that lowers the upshift speed, or backs off the throttle until the motor (and transmission fluid temp if there is such a sensor) is warmer than the the original ECU used in the shift map.

Can anybody confirm the existence of a clutch pack SB and if so, what are its specifics?

As far as nodified clutch packs, I looked and didn't find any service information on that, but when looking at parts info it depends which tranny you have. If it is a 722.624 or 722.636 there are modified pieces to the assemblies after a certain chassis number. If it is a 722.670 trans there show no modifications. The 722.670 trans has the latest pieces inside from the outset. Send me your chassis number and I'll look up the pieces.

Thanks! Is the chassis number the same as the VIN? If not, where is it?

Send me your chassis number and I'll look up the pieces.[/B][/QUOTE]

Yes, the VIN number. From the data card it will tell me what tranny and other special verions are on the car. It will also give the motor number, steering gear number, paint and interior numbers.

quack:

What was the result of your Nov. 7 trip to the dealer?

Thanks,
Rex

VIN of the E55 with the shifting problem is: WDBJF74H2XA894274

Thanks for the followup!

The service representative @ the dealer ordered the ECU referenced. I have another appointment on Nov 30.

You asked:
"What was the result of your Nov. 7 trip to the dealer?"