From what I've gathered, you have to trick the TCU into thinking it is always in neutral. Not sure if that is possible with the TCU version in your 96 which I believe is an EGS51. There's probably more than one way to skin a cat here though. EssiRS did a manual swap on his M119 SL, maybe you can reach out to him how he worked around the electronics.

M119 SL Performance Modifications

www.benzworld.org

This guys seems to have more or less pulled it off as well.

Hopefully this info will help set you off on a path towards other people who have done it and how/whether it is possible on your car.

 

From what I've gathered, you have to trick the TCU into thinking it is always in neutral. Not sure if that is possible with the TCU version in your 96 which I believe is an EGS51. There's probably more than one way to skin a cat here though. EssiRS did a manual swap on his M119 SL, maybe you can reach out to him how he worked around the electronics.

Thanks, this is great info. Spoofing the TCM into thinking it's in neutral is quite smart. I'll research more on this. I'll also see if I can get in contact with these guys.

Just my two cents -- the 600 is becoming way too valuable to hack up like this. The R129 is getting more and more collector attention and the 600 is the one everyone wants. And there are only so many left. Maybe just leave it alone.

No.
Let him continue. That's one less SL600, which would make ours more rare.
I've got 2 16v. So many kids have hacked them up. These 2 are becoming more valuable every day.

Hahaha, my rule of thumb is to never modify things to where they cant be put back to their original condition. I would like to be able to swap back if need be.

 

Just my two cents -- the 600 is becoming way too valuable to hack up like this. The R129 is getting more and more collector attention and the 600 is the one everyone wants. And there are only so many left. Maybe just leave it alone.

 

No.
Let him continue. That's one less SL600, which would make ours more rare.
I've got 2 16v. So many kids have hacked them up. These 2 are becoming more valuable every day.

 

I would be happy with a 95sl600 that had good plastic interior parts, good wiring insulation and a top that operated when asked to. The issue I see is getting a manual trans that will be geared to the 2.65 rear gear. Most of these transmissions are overdrive units and the sl600 has a 1to1 final ratio. This 2.65 will make overdrive useless under 75mph or so IMO. You also need a trans that is flex disk compatible, which limits the possibilities.
With the V12 you will need a transthst can handle a decent amount of torque, and if I were spending the $6000 plus to do this I would want a trans that fits the gearing and power management bill.
Ideally an older Mercedes manual transmission with a 1 to 1 final drive would be the easiest to adapt, but not sure it would meet the torque criteria. Good luck with your venture

 

I would be happy with a 95sl600 that had good plastic interior parts, good wiring insulation and a top that operated when asked to. The issue I see is getting a manual trans that will be geared to the 2.65 rear gear. Most of these transmissions are overdrive units and the sl600 has a 1to1 final ratio. This 2.65 will make overdrive useless under 75mph or so IMO. You also need a trans that is flex disk compatible, which limits the possibilities.
With the V12 you will need a transthst can handle a decent amount of torque, and if I were spending the $6000 plus to do this I would want a trans that fits the gearing and power management bill.
Ideally an older Mercedes manual transmission with a 1 to 1 final drive would be the easiest to adapt, but not sure it would meet the torque criteria. Good luck with your venture

I plan on getting a CD009 tranny. it's cheap and can handle the torque. I compared the numbers of the CD009 tranny's 6th gear and the 722.5's 5th gear and they're not too far off. Assuming a 20" diameter tire, cruising at 3500 rpm in 5th gear with the stock tranny will set me at ~104mph. 6th gear in the manual will set me at ~99mph. All I'm getting from this is that I'm getting a little bit more torque for a lower top speed, and I'm completely ok with that .



RPM @ 3500
Green = MPH

​

​	​	1st​	2nd​	3rd​	4th​	5th​	6th​
​	​	​	​	​	​	​	​
CD009​	​	3.78​	2.32​	1.62​	1.27​	1​	0.79​
722.5​	​	3.87​	2.24​	1.44​	1​	0.75​	​
​	​	​	​	​	​	​	​
​	FD​	​	​	​	​	​	​
CD009​	2.650​	20.8​	33.9​	48.5​	61.9​	78.6​	99.5​
722.5​	2.650​	20.3​	35.1​	54.6​	78.6​	104.8​	​

​

as for the flex disk, I plan on buying a drive shaft off eBay and modifying it accordingly.

 

Those gear ratios will be great. If you have the money, time and perseverance, I say go for it. Looks like you have done some homework and that’s a great start.

 

Ancillary but hopefully relevant........I'm not so sure the 600 model is "more and more collectable" I hope you are correct but I think we may see this trend in a few years. A decent looking 2001 with 97K miles just sold for $17K........probably a steal. I have seen a few low low mileage examples bring good numbers but I think many are scared of the alleged complexity, perhaps more of a myth. There's nothing like a V12!!!

FYI: I have a 600 with 53 miles......I bought it new.

I think a manual is a great idea........go for it.

 

What does a 600 have over the 500...speed wise? Probably..2 or so seconds in a quarter mile. Top end? 155...600 will get their a few seconds quicker....
Vett? More quicker. Porsche...more quicker.
BMW..same.
Quarter mile though...not getting to 150...
You tube has some races.. SL 600....quarter mile run...12 seconds at 102 MPH...

 

Benica:
The 600 is marginally faster but that's not what modern SLs are about. They are GTs, not sports cars. The biggest advantage is turbine like smoothness. There was a claim one could balance a nickel on edge on the intake manifold. I tried it years ago......true!

 

Amazing....what new things we learn!

 

Benica:

Slight clarification.......the nickel trip is at idle

 

DO IT!!!!

I've seriously looked into swapping a manual trans into my m113 SL500, got to many projects going on and my SL is my daily right now so it isn't feasible......yet.....one day though.

From my research with the m113 n/a motors, I understand that if you leave the gear selector plugged in but in neutral, the car will run fine, although the check engine light will be on. There may be a way to program this out, but tuners for 99 and earlier cars is getting increasingly harder to find, and whether or not they can actually do it remains to be seen.

Pedals can come from c230 / chrysler crossfire manual cars...and for all appearance do look like they will just bolt in, whether that is true for our cars remains to be seen.

You will need a custom trans adapter to bolt the CDO to the V12 which may also need a cutout for the CPS sensor.

You're also probably better off having your driveshaft cut or extended to fit.

Check this guy out, he manual swapped his 1st gen E55 and CLK.

 

So my SL is great but, id be a whole lot better if it had a manual transmission in there. I'm dead set on this, however, I would like to know a bit more before I start buying stuff. Mechanically I'm pretty much all set. I can fabricate my own adapter plate and modify things to work accordingly. My biggest concern are the electronics for which I have limited knowledge in. What do I need to know and do to get my car to work with a manual transmission?

- Can the transmission control module be removed with no consequences?
I'm assuming, and correct me if I'm wrong, it's just gathering info from the ECU to let it know when to change gears. So its not a vital part of engine operation. If that's not the case...
- Do I need to reprogram the ECU so it knows it has a manual tranny? Or can I trick it into thinking it has the original tranny?

all help/knowledge is very much appreciated, Thanks.

@roadhouse has done this. It's a lot easier on the 95 because the engine doesn't talk to a transmission ECU. You shouldn't even have a transmission ECU on a 95 with the 722.3 4sp.

 

Your right! I was out of town for the weekend but I had to confirm before responding. I checked the footwell and I don't see one. This is good to know. Also, I thought I had a 722.5 tranny but it seems I don't. I checked a vin website and as you said, I have a 722.3. Many thanks

 

Here is the skinny:

A) You have to figure the interlock from the shifter to the key
B) you have 722.3 it is basically a three-speed tranny. It takes off in drive from 2nd gear. 1st gear is actuated from a switch behind the throttle pedal that toggles a valve on the first front brake to drop the gear to 1st
C) Gear switch that tells the car is in park and reverse(for reverse lights). Got to figure that out.
D) then the HOLE on the transmission tunnel
E) Exhaust cross-over pipe
F) Trans Mount???
G) the front drive shaft
H) Matching the splines on the yoke out of the transmission....

In a month or so I'm driving from California to the East Coast possible swap out a 722.3 out of 95 CL600 and put a AMG 722.6 from a 2004 W215. I'm gaining the two extra gears plus the LONGEVITY and the uptick of 3 to 4mpg on the highway with three-times more torque capacity. it does requires a TCU which I have(aftermarket), It will have MB Factory touch shifter. I got everything, but the cross-over pipe might be pain... Most of it is Plug-In-Play. The 722.6's one can swap out bell housings, so I'm going from a deep M113 bell housing to M120 bell housing. Flywheel will be different for the large torque converter... That will look very factory with a W210 (2000-2002) touch shifter. That would be cleaner..

In both cases they are both lots of work....

Martin

 

Another guy doing a manual swap in a m119 r129.

 

Ahhh, I wrote about this 722.3 to 722.6 conversion a while ago...

Martin