ncmudbug

My wife's '06 C230 sometimes seems to downshift rather abruptly. When it happens, you can plainly feel it. It sort of feels like engine braking while my foot is on the brake. There is no change in the feel of the brake pedal. It doesn't happen every time but it happens occasionally. I have the tranny fluid changed roughly every 40,000 - 60,000 miles. There are almost 110,000 miles on it now..

Does anybody have any ideas about what might be happening?

MercWithaMouth

Im having trouble similar to that with my 06 C230 V6 as well. My check engine light came on today after an episode of my transmission not downshifting after a complete stop. I understand that the problem is in the conductor plate and TCM in these specific transmissions. It's the 722.9 transmission. I've posted asking about an estimated price to fix it. Also I think there may be a class action suit in the future because of the issue.
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ncmudbug

Thanks for the reply Merc. I was really hoping it would be because the fluid needed topping up. Do you know where the dipstick tube is and how long a dipstick you need? I thought I'd at least eliminate one possibility before paying somebody to look at it.

MercWithaMouth

I haven't even looked for mine yet but to my knowledge it's in the rear of the engine near the firewall. I looked on YouTube for it. The dipstick you will need to order and have shipped to you, there is not one with the car. It's between $10 and $20.

MercWithaMouth

I found Merc Benz specific dipsticks all over the internet (Amazon and eBay.) Whether they are specific to each transmission model would take more research on my part.

ncmudbug

Yep. I looked there and couldn't find it. I've seen dipsticks on ebay but they come in different lengths. I THINK we need the 1220mm length but I'm not sure.

MercWithaMouth

I'm sorry I don't have any more info. I know I'm going to be reduced to taking my car to the dealership. I'd like to have an idea of the cost and from what I've found on forums it's about $1200. The programming is what is most important. The TCM has to be specifically programmed to the VIN number of your car. I don't want to take a chance on a non dealership mechanic. Besides I also believe that after repair there's a 2 year warranty from benz.

ncmudbug

Understood. I think it might behoove you to find a good indy. The dealerships can be sharks.

MercWithaMouth

I live in an area where mechanics are intimidated by MB. I'll have to travel about an hour or more to find a dealership that might be reputable. The dealership here in my area IS a shark and they will tell me the entire transmission needs replacing.

ncmudbug

Good luck!

MercWithaMouth

Thanks! Likewise!

kwanchul lee

I had that issue few months ago with my 2002 c230k, found the transmission oil was low, so put the oil in. Now it happened again yesterday, my indi mechanic found the gasket of transmission canister must be replaced. I ordered it through amazon $14, I will see if this solves the problem soon.

MercWithaMouth

That's a good find. My transmission isn't leaking and the fluid level is correct.

ncmudbug

I wasn't able to find the tranny dipstick (or rather the tube for it) on my wife's car. In the end, it hasn't mattered since the behavior stopped without my doing anything.