DunninLA

I know this is a very strange topic, but I like to drive my car sometimes as though it were a manual... shiffing with the tiptronic, putting it in neutral when coasting to a stoplight, or putting it in neutral when coasting down a long, gentle hill.

About 10% of the time, when I coast the 2 miles from Mulholland to Sunset on the 405 South at about 65 mph, and then put the transmission back into Drive as i approach the offramp, the transmission does not engage. Basically I am without a tranny until the car gets under 25 mph and I have applied the brakes. This has also happened to me coming down the Grapevine into Kern County, and a few other places where I have coasted in Neutral at 60 or 70mph.

I have a 2001 E320 with 79k miles. My car has had this issue since at least 30,000 miles. I have an MB extended warranty which expires in November and really need to know if this is a design issue (what the MB service advisor told me), or if this is a problem with just my transmission.

Whenever I get a loander car from the dealer, which is usually a C240, it does not have this problem... the transmission always reengages when I put the shifter back into Drive.

I really like driving the car as though it is a manual (when I'm in the mood), but it is too dangerous right now if I can't get it back in gear.

mick1

wow. your driving technique is different than mine. I was taught that when driving downhill, the car has to be in gear, and not in neutral.

whoover

Coasting downhill is not "driving as though it were a manual." It's driving without proper control of the vehicle and illegal.

http://www.dmv.ca.gov/pubs/vctop/d11/vc21710.htm

Does the transmission not reengage when you reselect Drive and give the engine some throttle to equalize input and output speeds? If not, it sounds like a transmission problem. But high-speed coasting is not a sensible driving mode and I wouldn't swear that there isn't a design problem that was never caught.

lexrex

Have you by any chance ever read your manual? There's an explicit warning not to coast in neutral because doing so can damage the transmission.

DunninLA

Thanks Whoover, I had not been aware that coasting in neutral is illegal in CA... who knew?

I won't be doing that anymore then.

I guess I still need to know if it is a design issue or my transmission. I can't believe it is illegal to coast downhill everywhere in the world! MB must design auto tranny's to reengage after being in neutral as speeds over 25 mph... non?

DunninLA

You guys are too fast for me.... 2nd question answered by LexRex... thanks.

BTW my 320 has AMG 17" wheels, Eibach springs, Koni dampers, and Pirelli PZero Rosso tires.

patrick_y

Yes, very bad for the car. Automatics are not designed to coast. Mercedes says in the manual to use this only if in danger of losing traction on the drive wheels.

I know some people who've done that before, but they've never developed any problems from doing it.