adf111

2007 S550, 120K miles. What I dreaded happened.

Went on a 150 miles trip and noticed my RPMs were constantly 3500-4000, when usually it's 1,500-2000. I manually shifted speed down and it went to 4th (@75mph). Tried doing it several times,even stopped the car, turned everything off, the transmission was stuck in 5th. few hours later, drove back that same distance and everything was great meaning, 1,500-2,000 RPMs, shifting down to 6th.

On a busy street to day, I pressed the gas pedal to accelerate with a kick-down, and suddenly there's was extreme noise and the whole car vibrated, as if the gear was trying to engage, but it was too slippery. I took my foot off the pedal and everything works great. I've been driving for several days, with a very "gentle foot" (no kick-down) and thus far no problem.

I wonder:
1. Has anyone encountered something similar?
2. Does it mean transmission needs to be replaced?
3. I checked online and there are few low millage (39K, 67K) transmissions for sale. Does the transmission have the VIN stamped on it? Where? How to verify the millage stated by the seller?
4. Found in SoCal a company, selling a rebuilt for $3,500; is it a good price?
5. Any other suggestion?

Thanks for any info!

Mike5215

I had to replace the tranny in my W220. We used a reman unit out of Germany. Total was $6k installed. I'd prefer a reman with a warranty vs a salvage unit. I think mine was 2 years, unlimited miles.

bmwcrocop

The plate on mine went bad; $1500 back at 51,000 miles.

Tonye456

Before you replace the transmission have someone with a star diagnostic scanner check the conductor plate, when it goes bad it causes the transmission to not want to shift into gear and produces many of the symptoms you described. It's an inexpensive part and very straight forward to replace.

Mike5215

Yeah on mine the first gear clutch pack seized up and destroyed itself sending shrapnel throughout the tranny and torque converter.

adf111

Toney456, we checked it with star at the tranny rebuilding facility, and it said something about it being "slippery". They recommended to do tranny flush first. If that doesn't help, then a full replacement...

Funnily, I've driven the car, since the incident, with a gentle foot on the gas pedal, and it hasn't happen again.

Changing fluid is a $500 job. Do you think it's worthwhile?

marthyh

Guess that is a no-brainer and yes good results are achieved, especially if your do a Tim Eckart flush, which consists in using a special detergent before replacing fluid : http://www.automatikoelwechselsystem.de/automatic.html

Hope you can find a similar method where you live.

KNBS550

if anything the transmission fluid needs to be changed every 39k miles. Depending on when you got the vehicle and whether the previous owners did the work, if it hadn't been done then it's overdue.

DaveW68

I have always heard that you should NEVER do a trans flush, especially if the trans fluid is really black from neglecting to follow the schedule. What I was told is that the gearing in the trans could be worn and a flush could cause it to start slipping. If the fluid is really dark, you should change the filter and do a drain and fill every 10k miles until it's been done 3 times (to make sure you've cycled the old fluid through it since a drain and fill doesn't get all of the fluid out). Then you can get back on the regular schedule. The trans will never be in as new condition, but you might be able to get another 75k miles or so out of it before it needs to be replaced.