I have a 2009 e320 bluetec. Then the weather was 27 F and car first starts, the transmission seems to slip. RPM goes up and the car hardly moves. This happens both in reverse and drive. After about 1/4 mile, the transmission seems normal.

Is this normal for a diesel? Is the computer allow a higher rpm so the engine doesn't lug? 1500+ rpm for 2 to 5 mph.

How was your bluetec behaving during the recent cold snap?

+1 on ATF level. Low levels aren't always (in fact rarely) picked up by the TCM. Also, hard codes on the transmission often do not throw a CEL.

Is you car a 5 speed or 7 speed?

Check the ATF level, then go to a shop with a STAR diagnostic machine or equivalent that can read and clear transmission codes and get a print-out.

It's common for the engine to idle at a higher RPM until the engine is warmed up. Often around 1,000 RPM at freezing; even higher at -20C (-4F).

Thanks. It a 7G NAG2 transmission with ATF134 that was had a fluid change 2 years ago at an IND. I was not sure of the quality of the work. I supplied the parts and 12 quarts of Shell ATF 134. He said the pan was removed and TC drained. Said 8 quarts were used, but 6 quarts out of 12 quart case was returned to me.

This is the first time the car has seen < 30 F weather.

It could just be a slight bit low. When transmissions are a little low, they will improve as they warm up - the ATF will expand and the hydraulic properties improve when warm.

No tranny dipstick. Will need to remove un-carriage cover, etc. Is there an atf level indicator on the SDS STAR computer?
Now the weathers warms up, will the tranny codes be lost?

How's your initial acceleration when temperatures are below 0 C and without much warm-up?

I have a 7G. No transmission codes.
1st INDY said low ATF and delayed shifting into R and F. Said fluid was burnt. He wanted to do a flush using genuine Mercedes ATF without dropping the pan. That would be $400 in fluid alone! I said wanted pan dropped, TC drained, filter changed and visual inspection for metal in the pan. He didn't want to work on my car and charged $104 for the diagnosis that I paid. From the spilled ATF on the car, it smelled normal to me.

2nd INDY did as instructed. No tranny codes. He noted ATF was clean and fresh, no burnt smell. Filter was on the disconnected on the bottom of the pan. Normal to low amount of metal in the pan. Filled with Shell ATF 134, ran until 70 C to get air out of all the lines, let cool over night, and adjust fluid level when at 45C with scanner.

It's warm now, so I don't know if the the problem of no acceleration for a few minutes at

I've had low tranny fluid before, and it always surprises me how well these transmissions (5 and 7 speed) run on low fluid. It seems that if you were to err in fill volume, it's better to be too low than too full.