Merc63

Changed fluid in the trans last weekend and I'm slipping and cutting power into 4th gear again now.

This is identical to the last issue I had, to a T. Right after a fluid change, with mb fluid and filter.

For some reason these clutches don't like new fluid being put to them, maybe it takes the varnish or something off the clutches. This is no coincidence that it's happened twice now.

Trans was shifting hard and zero issues prior to fluid change, completely pissed at this point. I've emailed weistec for their input, see what they say..

I'm going to try drop most of the fluid out and change to amsoil which is mb spec and lists friction modifiers for clutches.. only obstacle is trying to reset the trans from cutting power between shifts now? I think it detects the slip and goes into a protection mode..??

Does anyone know which clutch does the 3-4 shift?

deadlyvt

That's ****ty and weird. Does weistec ship the transmission with fluid or just recommend you use the mb fluid?

Merc63

They ship it empty..

Adi-Benz

I feel like the tl;dr for ALL mercedes transmissions after 2006 is

change fluid
need new trans

and it's pretty stupid. From C's to S's they have this issue. Yours is aftermarket tho idk

bhamg

Hey Merc - I'd be cautious about changing fluids. The boutiquey ATF's seem to have much higher levels of at least one, and often two friction modifiers like zinc and phosphorous. Might that help or hurt? Maybe the latter...

And they all have increased detergents/dispersants like calcium, magnesium and boron. Factory fills seem very vanilla in their formulations so the temptation is there to beef up the next fill but IMO proceed with caution. My $0.02.

dubzAMG

My weistec trans was shipped without the plastic over flow tube installed.I discovered it when I swapped out my OEM pan for theirs...

Plasar

FWIW, my 2 cents:

* I had all fluids changed at 50K when I bought my used 2012 C63 Coupe - had the work done at MB Pleasanton - tranny, diff, etc.

* No real difference before/after that I could tell.


Now my stark realization:

* I think the MCT transmission is just a lame part of the car - compared to a real dual clutch (ex. E92 BMW M3), it's slow, it's slippy sometimes, the paddles are a joke (forgetting shifts/not keeping up with shifts). I've kind of given up on it.

Love the car overall, MCT is the Achilles Heel (queue Led Zep "Achilles Last Stand"... done by a middle school cover band... using a $200 drum kit, a Korean Strat, and a buzzing PA - laaaaame).

Critter

Purchased the Weistec Transmission pan for 07 E63. Had transmission shop change out the oil and replace filter and reinstall new deep pan.
Tech explained to me to run the car softly for a hundred km.
This I did except for a spirited on ramp run at around 50km after change.
The transmission is no issue to me and performs as required.
The trans pan I would suggest to any one as it does have increased capacity , twin magnets, good flow baffles, black and beautiful ha ha . Next oil change is smoother as the pan has two openings, one fill and the other level amount.
To change out to fresh oil and then flog the car, Merc trans does not like and will give poor results for sure.
Possibly the take it easy idea is to go softly on the clutch surfaces and reinstate proper friction control. IMO

Merc63

The car was drove all week after the fluid change, now that I realize this is an issue. critter it would make sense to drive it easily for many weeks to allow the clutches and fluid to mate up again and the trans time to adapt to the new fluid.

I'm also wondering if the tolerances in the clutch packs were set correctly from the get go. Was doing some reading and seen a fluid change that causes slip is a sign of wore out clutches. Being refreshly rebuilt under 15,000km ago, I find it hard to believe they could be wore out already.

I found a shop in Toronto that has experience with these trans and installing AMS clutches. He also mentioned the importance of machining a piece to set the tolerances in the clutch packs. With a 3 day build time and being in the same country, I'll likely go this route if a forced adapatation doesn't help.

shardul

iTrader: (1)

Message me if you want a AMG clutch kit I can get it at a discount. I have supplied one kit to the same shop in Toronto.

ritalin

TAT is definitely the place to go to. Bob and Matt will take care of you.

Merc63

Thanks I'll grab one soon.

How did the trans build go for you? How's it shifting etc now?

deadlyvt

Did you contact weistec because like you said lasting 15000 km on a "bulletproof" transmission is pretty pathetic

ritalin

Trans feels so much better now, the driveshaft helps w overall response, it truly feels more direct and connected at the *** end.

I have not had time to hit the track and i don't have a real power adder yet, so i have not really put it to the test. Hopefully i can go in the coming weeks.

Merc63

I don't think they refer to it as that on their site anymore... I've been chatting with them and they've made some suggestions to try. Force adaptation and cleaning solenoids, which I will try first.

Another weird fact, trans shifts fine in C and S mode, but M it cuts power into 4th. It did this last time, but I find that strange how other modes shift normal. I've been driving around in C mode hoping it just needs to break into the new fluid and adapt the fill times more. We'll see what happens.

Jasonoff

That would suggest it's not mechanical then.

Merc63

You would think so, but this is the second time I've had this issue.

Jasonoff

Does the TC absorb more slippage when in C and S letting the clutch pack engage vs M?

Do the valve body solenoids behave differently in C and S vs M?

deadlyvt

I read somewhere what each mode actually does in the transmission but I'm unable to find it
if I remember correctly the line pressure and clutch engagement was the highest in manual mode
Although it makes almost no sense then that he slips but only in manual mode ...

Merc63

I think it was slipping for a few shifts at the track, then it goes into a cut power similar to a rev limiter shifts then applies power now.

roadtalontsi

3-4 is k2 clutch. My issue is always the k1 clutch on 2-3 shift - but mine is still stock. time for rebuild part 2 lol. I dont see how a fluid change could bring about this issue unless it was just nasty. transmission flushes normally dont cause problems unless they dislodge particles and clog things. or the fluid level is off.

Other people commenting without superchargers - its pointless. This is not a normal car. This is a daily driven blower car. thats a big difference compared to headers and tune lol.

taking it easy after new fluid? uhhh what kinda junk do they normally work on. , i could see that on a new fresh rebuild but not a typical service

Merc63

Do you think it could be an adaption issue with the new fluid? C and S mode shift fine but only M does it? I've been driving in C mode letting the fluid beak in and hoping for some adaption... I did one hit last night and it shifted into 4 fine in M mode...

What clutch does the 4-5 shift? I have no problems with any other gear... so weird.

deadlyvt

When you changed the fluid did you flush the cooler and lines to and from the cooler?

Merc63

No simply drained pan, removed, switch filter, filled with 5L ran to temp, drained excess and plugged.

deadlyvt

perhaps as the old fluid mixed with the new fluid it created a different amount of friction on the clutches and the transmission detected this as clutch slip and went into limp mode ?
In the future it's simple to drain the cooler either unhook both lines at the transmission and use a fluid pump with fresh fluid until it comes out the other end or if you have a helper get them to sit in the car disconnect the return line and with the transmission full run it a few seconds until the dark fluid turns turns into fresh shut the car off then refill