boquanzhu

my 04 C32 has some problem which dealer cant even find out whats wrong with it. the car has 48000 miles and when its cold, the car bangs into gear from first to second gear around 2000 rpm,like it hits a bump. and it has no probem on other gears. it will go away after driving for 5 to 10 mins and it happens only when I just started the car. when it warm up, the problem will be gone, and shift smoothly. the dealer did a DAS test with no codes, and checked adaptations and oil levels are OK. and they did update software on the car. the dealer told me it migh be delay shifting when the car is cold to make it warm up faster. but i really dont think its the case. if anyone has idea what this might be, please let me know,

loungn14

Possible suggestions would include:

1- The car is very smart and adapts itself to your driving style. Reset your ecu and see if it fixes the problem (search ecu reset)

2- TCU - Traction control unit- There was a reflash for this a while back but im not sure that it covered the 04's Search TCU flash- They might have done this..

3- Glycol Contamination- Older c32's had a problem with their radiators that leaked into the transmissions. Search glycol on that one....

These are the typical things we see with that problem....there are others of coarse...

pointman

I thought 04's were glycol free.

boquanzhu

will reset the ecu remove the upgrade software they put in the car?

loungn14

nope

Vomit

My 02 does the same thing. I am 99% sure that it is the torque converter which, when the transmission is cold, locks up under any thing more than very light acceleration. It really is quite shocking when it occurs. . . sort of feels like you just came to the end of a chain attached to your rear bumper. Not sure if there is a fix for it. I just make sure to stay really light on the go pedal until the car is warm (which is a good idea anyways). For more info, search "torque converter." Hope this helps.

c32used

+1

c32used

I believe the 03-04 were less likely to glycol problems but not immune of it.
The issue has been worked on for many years but got better after MB was more sure of its cause...they updated the original Valeo radiator among other things but they are trying to find cheapest way out if not pretty sure its very costly to them.

pointman

Damn it. This whole glycol thing has me scared owning the 32 long term.

loungn14

no worries my friend.....if your that uptight about it check ur can and see if you have the valeo radiator. If you do, just swap it and your fine...

ohlord

did not have the Valeo problem.
You readapt the tcu not the Ecu.Probably not the problem either.
722.6 transmission had a TSB issue order for shifting problems and resolved with fluid and filter change at 39k miles,mb spec fluid.
They are shining you on about the delay for warm up,the secondary air pump kicks on and fires up the cats in less than two minutes.You might feel a slight upshift in that period,very slight.From your description it sounds like a solenoid or pressure problem,it should not be banging gears.Find a good indie shop,that dealer is heading you towards a new transmission.

pshek

I would do as described above. Have the shop check the valve body and fluids. Could be a valve sticking. Then see if that helps and you can do the TCU adaptation after R&R the valve body.

Newzchspy

What type and octane of fuel are you running?? Are you throwing CELs

c32used

He wants a solution not a joke

pshek

c32used

+1

Newzchspy

+2

timberman

I'm having a few gear change issue myself at the moment

I've had the typical 1500 rpm jerk for several years and never found a cure so I've just learned to live with it

lately it's gotten much worse, I'm often getting a thump in the back from all gears up and down even after the cars warmed up + the changes seem to be all over the place sometimes refusing to change up even when I use tiptronic which is pretty annoying when I'm cruising at 35-40 and still in 3rd gear

also sometimes it seems to change up or down in the middle of a bend which I thought it wasn't supposed to do

I've been holding of going to the dealer due to not having any warranty and being a little worried about what they might find

I replaced the radiator about 18 months ago and had them replace the transmission fluid so I'm thinking it's not glycol contamination and possibly related to either the tcu or torque converter/ valve sticking
I'm sure it won't be cheap whatever the problem

pointman

I am embarrassed to say... but I am not sure how to get to it to check and see.

I know that I had the "coolant circulation pump" replaced not too long ago. But thats about it.

pointman

You sure?

Fifth Ring

New battery? Seems to fix everything!

Bobby Dazzler

Pete

I had much the same. Dealer changed the oil (supposedly) but not much change. Worsened as you described. Took it back several more times.

Took it to a different dealership, who spotted transmission oil was low and topped it up. Now much better.

Either they didn't top it up or they didn't put enough in!!

Bobby Dazzler

Does the secondary air pump not kick in until two minutes after a cold start?

If so, would it cause a vibration through the car if stationary in Drive with foot on the brake?

moosejaw

Will this ever die?
and does your mom still pack your lunch?

timberman

awesome,thanks Rob

I'll take it back to the dealer and ask them to top it up for me