vshengr

Hi MBWorld, new owner of a 2002 C32 AMG with 107,000 miles.

I've had the car for roughly 3 weeks and noticed issues when starting the car for the first time each day (temps have been between 30-60 F) or after the car has sat for 5+ hours. Car was already warmed up when I test drove and seller said to make sure I warm up the car before driving. Little did I know?

On a cold start and driving from stop sign to stop sign, the car will shift maybe once or twice between 1st and 2nd but eventually stay in 1st gear. The supercharger will kick in for the first few seconds but after one or two gear changes it shuts off completely. The engine sound increases but I have very little acceleration. The car also will get stuck in 2nd gear when it needs to shift down into first (rolling to a stop and then needing to accelerate out of the stop). It will seem like it's not in any gear for about 2-3 seconds then finally shift back into 1st, at which point it will remain in 1st gear moving forward. If I try to use the manual shift option, same thing happens (no supercharger, slurrs 2nd gear and then stays in 1st). If I leave in D and never manually change gear, then the shifter locks me out and no matter if I push left or right it will stay in D and will not change gear. If I come to a stop and put it in park (don't turn off the car) then shift back to D, the car simply stays in 1st gear and does not let me shift out of first, no number comes up, it simply reads D. By this time the car is around the 60C mark and it feels like the supercharger is working? But it won't shift out of first (have not tried going over 30mph). Also the car will not change from S mode to W or vice versa.

All of this happens while the car's temp sensor reads between 40-60C. However if I simply restart the car once the car temps reach 60+, everything works perfectly. So for the past few weeks, every morning I have to drive a few blocks with these issues and then restart the car once it reaches 60C+ on the temp sensor. Once warmed up, everything works perfectly - transmission, supercharger, etc.

Any ideas on what might be the issue? I've seen lots of similar posts about supercharger issues or getting stuck in 1st but most of those lead to some significant failure of some kind and typically after a few 'restarts' the real problem appears and the car becomes undriveable until fixed. With mine, the car truly is perfect once warmed up???

All help is much appreciated!

C3Duece

sorry I don't have any answers for you but have you searched the forum? There's a wealth of knowledge here and it only takes a few mins/hours to find what you need. Good Luck!

vshengr

Thanks C3Duece, I've been reading up for the past 3 weeks but with no luck

Many people with similar issues but not quite the same. Most people get multiple errors on the display and check engine light etc but I get absolutely no errors. I don't believe it to be the super charger clutch or the inter cooler which I've read plenty about. Without fail, once the car is warmed up and restarted - everything works perfectly and has been replicated about 15 cold starts in a row.

I read something about the torque converter locking up automatically because the engine/tranny are trying to get fluid temps up? In that scenario the person said their car would 'unlock' the gears on it's own and the thread died, not even sure it was mbworld. Mine thus far hasn't 'unlocked' out of first gear on it's own. Needs the car to be restarted before it unlocks.

Thank you to anyone reading this, I simply haven't found any threads with a solution. Any thoughts or suggestions you can provide would be much appreciated.

Duncan64

Do you know if the car has a tune?

Lenin

vshengr, take the car to a shop with the STAR diag system and let them check all the codes. You may have hidden codes but no CEL. This is where I would start. The fact that you can not change between W and S mode indicates some kind of a transmission problem. W puts the transmission in second gear. The car doesn't need to be moving to do this. That's should be a very simple operation. One other simple thing to check is the TCU. It is under the carpet on the passenger side. Make sure that the cable harness is not wet (water or oil).

vshengr

To my knowledge, no tune.

vshengr

Cable harness is dry. I'm only locked out from being able to switch between W/S on a cold start. Once the car temp sensor hits around 60C and I restart the car, I'm able to switch between W/S at any time and everything works perfectly.

Any one else ever experience anything like this?

I'd like to get an idea of what I'm in for $$$ but looks like I'll have to get it checked out through star.

Thanks for your input!

Duncan64

Could you ask the previous owner? Ive had other cars before where the tuner disengaged any boost buildup until the car is warmed up. Thats the only reason if what you say is true that the car behaves perfectly after its warmed up then something (BUG) in the ECU/TCU is causing the issue.

vshengr

Ooh that makes sense to me, will ask the seller again as it seems he hid some of the known issues.

Thank you for the insight!

Lenin

Never heard of this kind of a problem with a tune on a C32. Don't think our MB tuners even know how to do this on purpose. The supercharger doesn't even engage until about 1800 RPM.

vshengr

Contacted seller and he said that there is no tune to his knowledge. He said that this only happened to him once at which point his mechanic said the tranny fluid was low so they topped it off and the issue went away.

So I just ordered Shell ATF 134 and will attempt this when it arrives. Fingers crossed that this is the issue!

Lenin

Are you going to add fluid or change it?

vshengr

Seller said he changed the fluid and gasket shortly after that was resolved. So I think around 95000 miles, I'm at 107000 miles. I haven't had a chance to check the fluid level as there is no dip stick and supposedly need a special tool. So was planning on waiting for the fluid to arrive then take to my indy shop for them to check the level and top off if necessary?

firstshadow

That doesn't sound good, check what brand your radiator is ASAP!

Supgee

Hello.
It sounds like to me you are stuck in limp home mode, with a fault with your transmission.
To me it sounds like the transmission is low on oil. Try adding only 100mL if you have the fluid and see if it helps. It sounds like the TCU is not letting it shift.
Other possible causes are: transmission electrical plate, one of the speed sensors is no good (common, valve body has to be removed to complete the repair)
if the fluid is low, it is leaking. there is only one common leak on this 722.6 transmission and it is the transmission adapter plug that connects to aforementioned electrical plate on the bottom of the transmission.
glycol contamination of the transmission oil due to a leaking radiator.

I would advise not driving the car also, this transmission is about $7000 re-built... and you don't want to have to do that.
The best thing to do is take it to a shop with a STAR Diagnosis, where they can communicate with the transmission control module and see what is going on. I am thinking it is low oil, or faulty speed sensor. Good luck!

vshengr

Taking it to my indy shop tomorrow morning to check the tranny oil level. That honestly makes the most sense. When the car has sat and is 'cold' then the tranny does not have any fluid for lubrication. When the car warms up and the fluid gets moving, even though it may be low on fluid, it will eventually provide enough to get the car operating like normal. I'm hoping that's the case and that the signs thus far have been the Merc tranny trying to protect itself.

Also I'm noticing that my fuel economy is hovering around 12mpg city driving. I had a G35 that was burning through engine oil and was also getting around 12mpg city driving. In that case the engine being low on oil meant the engine was not running optimally thus the poor mpg. I'm thinking that with the tranny not running optimally, it is also affecting my mpg on the C32.

I'm assuming the radiator was swapped out, otherwise no way it would have made it to 100,000+ miles? I'm the 3rd or 4th owner of this C32 so unfortunately records are not readily available. But as previously stated, the car drives perfectly when warmed up - minus the poor mpg which I'm just now noticing.

I'll update tomorrow after it's been to the mechanic. Thanks all for your insights thus far!

Lenin

Make sure the shop has a STAR diag system. If not, it will be a waste of time and money. And don't assume anything. If the previous owner changed the transmission fluid 20K miles ago and you are already short of fluid, where did the fluid go? These transmissions should be good for at least 60K miles before needing any servicing. Let's it's not what Supgee was saying. Because it sure sounds like it.

vshengr

So my local indy shop doesn't work on euro cars and I didn't want to keep driving if I was running on low trans fluid. So I went ahead and did some searching to locate my transmission fluid tube, based off pictures I was looking for a cap with a red clip or simply a cap towards the top left of the engine. I spent a good 5 minutes confused because I could not locate any cap. Then upon closer inspection and matching pictures, I found an exposed tube with no cover/cap.

I went ahead and dumped .5 liter of trans fluid in since I don't have a dip stick long enough. I was going to buy online but I don't want to wait a week and i didnt want to drive at all if i was low on trans fluid so I plan stopping by a hardware store to buy a wiring snake of some sort. I've found that the correct oil reading should be 171 mm or 6.7 inches from the bottom of the pan. And from the top of the tube to the bottom of the pan is roughly 29.5 inches.

Anyways, dumped in that .5 liter and fired her up and let her idle for about 1 minute, then off I went. The tranny took about 6 shifts between 1-2 before it locked up, usually takes only 1-2. Once it locked up I shut her down and added another .5 liter of trans fluid. At this point the car temp sensor was still only reading 50C so not properly warmed up. Fired her up and off I went without a hiccup. The transmission definitely felt smoother, shifted quicker and it felt like I had much more power and better throttle response. Drove it for a few blocks then parked for about 1.5 hours. It's about 30F today so pretty cold but I'm not sure that was enough time to reproduce a cold start, either way I needed to get to work. So fired her up, idled for 1 minute and pulled out. The car internal temp sensor at this point was still at 40C. Tranny operated perfectly and mpg was steady around 16mpg.

So I'm no mechanic but I'm guessing that with no cap or cover for my tranny fluid, the fluid eventually evaporated? If it that's even possible?

Found lots of auto tranny complaints about no fluid left when people went to change their tranny fluid. Those didn't come up when I searched cold start issues since I didn't think it was a transmission issue. Tons of threads complaining about tranny lockup and realizing no trans fluid was left in the tranny.

So I believe that was my issue. Mercedes was pretty smart in programming the tranny to protect itself when levels are low, I just wish they would have had some kind of dash warning? Unless my sensor is broken? I plan on taking a reading this afternoon and then replicating a full cold start tmrw morning. I purposely have submitted long posts with lots of details hoping this will help someone else in the future! Check your trans fluid level if you have trans lockup issues!

C230 Mulac

Welcome to the forum.

Have you previously owned and had experience with MB's? Reason I ask is, even though it seems you have fixed the problem, I would still take it to a shop with STAR and have them check the fluid level and everything. Driving with TOO MUCH fluid is not good for the transmission either, and it seems like you were sort of "guessing" by adding 0.5L at a time. Maybe I'm just very meticulous about my car, but these are very particular and require a lot of precision with things like this. Honestly, I would just go ahead and do a full tranny flush and replace the fluid.

Anyway, good to hear your problem seems to be fixed. My other recommendations after just recently buying the car: brake fluid flush, coolant flush, check the air filters, @107k miles there is a lot of stuff that should have been done before, but if you don't know from the previous owner, these are a couple of things that you should just do so you know you're starting fresh. There are probably more things you could look at but definitely start with the 3 fluid flushes.

vshengr

Well I tried again on cold start and same as yesterday, was able to go through about 5-6 shifts before it locked up in 1st. In total I've added 1 liter of fluid. After restarting the car, tranny unlocked and returned to normal.

I am actually sitting in the waiting room of a local shop that specializes in mercs. They are going to check the level and top off if necessary. I'm hoping that it is still low on fluid thus still going into limp mode.

The added fluid definitely has helped a bit, we will see how much was actually present in the tranny.

Will update after I talk to the tech.

Lenin

Specializes in mercs meaning they have the STAR Diag computer? Because if they don't have it, then they don't specialize in MB. And if they have it, let them read all the codes while you are there. Including the hidden codes. Don't mean to harp on this but that's where you should start.

C230 Mulac

+999999

Like I said before, these cars are particular and you need to make sure you're going to the right people. We are just trying to help you out...good luck.

bigelv

As mentioned above its best to get it to a merc specialist.

Putting too much oil in the transmission can cause leaks as the pressure builds up. Pushing oil through seals etc..
I had similar problems to you a couple months ago.. Lazy and erratic gear changes..First thing I did was check for glyco contamination.. Thankfully was clear even though I have a valeo rad and 120000 on the clock..Then put it on STAR..

Long story short, ATF flush,TC and valve body rebuild... Good luck

Gramma_Benz

yeah dude, I would NOT be trying to diagnose yourself and keep stressing out the tranny like that. What you're doing may lead to you having to replace the WHOLE tranny in the end. No bueno and tons of $$$. Just go to a proper MB tech and let them diagnose.

You shouldn't be driving it at ALL at this point. I'd even tow it to a mechanic.

macbryanie

Doesnt sound like it but, If it turns out to being a shifter I have a new one that I bought from the US to save some coin,I realised my error when I had already paid for it. I end up buying one second hand in AU. Front the shipping cost and all yours as its completely useless for anyone down under.