jcmbz

Have kept the cars for a few years and finally have the money to do the 55 swap. Located an engine out from a CLK55 and have my mechanic to do the swap.

The swap is not hard but have some stories. And it was done a few days ago! Car start up fine, idle seems a little bit low on 600rpm

Using the old 43 ECU and the wiring harness and did some modication for the coolant pipe.

So last night finally can test drive the car. Here are the problems

1. Car drives ok under 2000rpm, shift no problem
2. Sometimes car do not want to shift until 2500rpm
3. Once the hit higher rpm, say 3500rpm, the car will not shift anymore, feel like enter into limp home mode.
4. When this occur, if I hit the gas hard, the rpm will go up but the speed did not catch up (feel like the tranny is slipping, no ESP light on at that time)

Mechanic try to pull out the fault code and said my tranmission cannot handle the torque from the new 55 engine. He suggest me to upgrade the tranny.

So I would like to know, is the 722.631 (NON tip) tranny is not able to handle the 55 torque? If so what other tranny I can swap to? Can the one from a W220 S500 (with tip) can be swap?

Or I can only limit my option to 55/600 tranny?

Sorry for my poor english and look forward to your opinions. Thanks!

Sulaco

Mechanic is incorrect. The transmission is exactly the same as the 55 transmission internally. The only difference is the output shaft is made of another material.

I've been driving my 55 swapped C43 with my original 43 transmission very aggressively for 15k miles, it's fine. Had 200k miles since last rebuild on it before the swap. Just service normally and all is fine.

you have an electrical issue. Fluid in the tcu connection or cracked conductor plate. Do not throw money at a new transmission.

jcmbz

Thanks ！
my mechanic has a number of test drive and every time when the car won't shift after the mechanic hit the gas harder, which mean the rpm pass 3000. The 722.631 shift fine if he treat the gas paddle gently. Once the car wont shift, mech will need to pull the code. Every time the code is different.

I will have him to check the granny again.

Thanks for your information ！

really hope to get the c43 ready with the 55heart!

DRBC43AMG

Agree 100%. The transmission is already the heavy duty version of the 722.6xx for high torque and is more than capable of handling the 55 and even more with no problems. You just need to service the transmission with regular ATF flush and filter change. I do mine every two times I do the engine oil and filter. Works like butter even with WOT

KJI3jflarryfe93

Only problem is the sungear X-ploding inside the tranny, then you have a pooped tranny.
Brass bushings are made of weak material on early 631 transmissions 1998.
From 1999-2000 trannies were better.

Change tranny oil and filter on regular basis.
You can also buy the extra magnet which came on newer cars.
C43 never had this magnet.
It's rectangular shaped.

Don't thrash your tranny when it's still cold.
In city driving use only the 4th speed not in D-mode.
Some peepol used to claim tranny oil heats up more in D-mode in city driving?!
Don't know if this is true or just an urban legend, maybe our spezialists can confirm this?

DRBC43AMG

What the heck is sungear??
My 99' has the magnet, but don't know if it was added after construction, or came as standard.
Never heard about blocking the transmission in 4th gear. Mine stays in D and works perfectly.
Agree that you need to get things hot before hard acceleration. Same principle for all machines

KJI3jflarryfe93

i bought an extra magnet for my car besides using factory tranny magneto screw

i have pictures of the sungear in shrapnel let's see if i can dig them up?

jcmbz

Thanks everyone for the input!


So the shop tested the car again, changed all fluid and said there is nothing related to the electrical. They said the tranny was gone bad.

So here is my options:

1. Get a tranny from the 55 or 600 car... which is very difficult to locate one. Even if I can the price will not be cheap. EST price around USD 800-1000 tranny only
2. Use a M113 S500 gear box from W220, price is around USD400, plus parts and the EST price is around USD1000-1200 with labour

3. Rebuilt the C43 tranny. EST price around USD1600. Which I think I will go this way. The only thing I can think of if there is any parts I can get upgraded if I told the shop to rebuild the tranny?

Thanks again for everyone's input!

really cant wait to feel the 55 in C43!

DRBC43AMG

If you get your 722.631 rebuilt, I would recommend getting stronger gear packs installed. That will really beef up the transmission beyond most thrashing you can throw at it.

BTW have you seen this 722.6 manual? Guess it's the bible regarding this transmission

jcmbz

THanks mate!
Reading your post, you mentioned This was solved by stopping, cutting the engine, starting again and driving away with a light foot on the throttle going up the gears to 5th.


Exactly the same as mine. if light foot the tranny shift ok... not 100%normal but it still shift. Once with heavy right foot. The tranny wont shift anymore......

Then after stop sign, the tranny will shift from 1st to 2nd, and that's all.... and kinda feel the tranny was slipping too

John575

It swap made in Kazakhstan, country in a Central Asia. If your mechanic don't make elementary swap from 4.3 to 5.5 - he is bad mechanic.

DRBC43AMG

Reading the thread again, I think your mechanic is taking you on a snake ride. If your tranny is behaving like you describe, there must be error codes stored inside. Make sure he is using a scanner which is compatible with MB vehicles.
From my experience, I would say the conductor plate is faulty and needs to be changed. If you want more info, go read my 2017 Spring preparation thread (see signature below)
Forgot to add that if you have codes related to the conductor plate, the mechanic will need to erase the code, otherwise the tranny will remain in limp mode. Why? I serviced everything and forgot to to erase the code. Plug in, erase, plug out, drive away

PJmak

So trans was fine before swap but after swap it has gone bad?

I call BS bro. Change your mechanic.

loggato

When I put an M113 in my R170, the "high torque" 722.6 that came with it would not shift out of 2nd if the throttle was past half way. it also had a couple of floating issues. also would go into limp mode if I cornered too sharply. I believe the issue had to do with the conductor plate. I ended up swapping the bell housing onto my original R170 722.6 and it has been fine ever since.. except for some slow shifting.

cm60k

I could be wrong; but really not worth that damn headache with much $$$s, putting M113K into C43,

compared to get many models of 55K dolls,,

55N/A with good mods., will be great to poping with..,,

sorry, it's my own IMO..

-;ZAYED;-

cm60k

^^Have to agree with this^^..

-;ZAYED;-

jcmbz

Dear Guys,

Turn out the tranny gone south.... It is not easy to get an 55/ 600 tranny so my mech. just swap the tranny from a W220 S500 first. He said the car is working fine now. I will pick up the car tomorrow and let you guys know!
Thanks for all the input!

J

DRBC43AMG

Hey, it would be very interesting to know what went south with the tranny!

jcmbz

He had mentioned to me that my tranny was not " healthy" i think a year before I did the engine swap. At that time i feel my car still drive perfectly so what I did was the regular transmission oil change
He is a good mechanic and he used to drive a W202 230K

jcmbz

Finally got my car back and WOW, the car drives amazingly!
The power, or I should say the torque, was so powerful and it really give a different character to the C43!

My mech show me my old tranny. He dropped the pan and found tiny bronze shavings on atf and the pan. He also mentioned and suspected K2 clutch drum bushing since the car was produced in 1998, having the old design K2 drum bushing.

Anyway the car drive ok but he said give some time for the tranny to learn. I will keep you guys update!

jcmbz

I love the NA 55 engine and I should have enough fun with this powerplant.
Also it is not legal to drop the 55 engine into a 43. However it is not easy to tell and the cops will usually let you go coz the engine bay looks original.
Will be a different story if you put the M113K in it........... too obvious

mickey13

nice!

DRBC43AMG

Nothing is legal in the 43/55 engine swap and I doubt you can get the conversion road registered without some major hassles, at least in my part of the woods. However as both blocks are identical, I doubt any technician or law enforcement officer will know the difference, without checking engine serial numbers and that is difficult as you need to know where to look...

jcmbz

Once I done my transmission swap, there is another CLK 55 pop up in the junk yard! Damn!

So here is my questions:

1. Is the 2001 CLK 55 brakes better than my 98 C43 brakes?
2. Both of the side mirrors are not working except for the folding function, should I swap the mirror with the CLK one?
3. The CLK has the +/- transmission. Is it hard to swap that? Can the CLK instruct cluster direct fit the W202?

Thanks!

Sulaco

It blows my mind that this engine swap could be illegal anywhere. What a world!