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  #1  
Old 11-23-2014, 10:37 PM
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722.6 on OM603 TCU or ratchet shift?

Hi all! new here,

I recently purchased an 87 300d turbo from a guy and ive managed to replace the heater blower, speedo cable, new fuel filters, fix the boot lock etc without having to resource to asking the forum anything (yes the search function does work very well)

However I am about to drive this tank on a road trip from houston tx to oklahoma city in a few days and I cant help but notice my AT doesnt have a lock-up torque converter... ALL of my vehicles thus far have had manual 5 and 6 speeds since I really dont trust automatics that much. But since I want this car to be a cruiser with some power (in the future) I want to be able to lock everything up for MPG's.

I have been reading around and looks like the 722.6 is a good option however its solenoid shifting wizardry requires a smart computer etc. Then I came across a fellow that used an arduino to control it. This is not far outside of my ability however what im wondering is can it be MANUALLY shifted with a ratchet shifter?

Thanks in advance!

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  #2  
Old 11-24-2014, 08:56 AM
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Inquiring minds want to know!
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  #3  
Old 11-24-2014, 09:33 AM
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I would be very worried about trying to homebrew code for an Arudino to control the transmission. Unless you happened to be on the development team back in the day in Stuttgart or wherever they did this. Not knowing the limitations of the system would make me not want to drive the car in anything but a lab exercise on a closed course.

I then started thinking about what would be the implications of swapping the control systems from a 98-99 E300 Diesel into this car. (I'm on vacation this week so I got bored...)

Fuel - should be able to swap the mechanically actuated 603 pump for a 606 electronically actuated pump no problem.

Transmission - will a 722.6 share the same mount points as a 722.3? Both the bell housing and the transmission mount to the frame?

Pedal control - that is actually pretty easy, the mechanism on a 124 and 210 is pretty similar, a Bowden cable into the passenger compartment. On a 124 the Bowden cable goes to the Rube Goldberg mechanism on the IP, on a 210 it goes to the rotary sensor by the brake booster.

Here is where it starts to get weird.

The electrical system in the 124 (especially 1st gen) is all direct point to point control. For example, the cruise control is an entirely independent subsystem and mechanically controls the IP and gets its speed reference from a Hall effect sensor on the back of the speedometer. The dome lights are direct wired to the door switches. The climate control is independent. The speedometer is mechanical, the other gauges are all wired direct to their sensors. The engine start control is key switch terminal 50 -> NSS -> starter solenoid. Power windows are directly switch controlled to the window motors.

The W210 is completely computer controlled. Almost every body electrical device gets wired to a SAM module and the computer decides what to do.

For example, opening a door now means: door switch contact made -> SAM module -> CAN bus message "turn on the lights" -> another SAM module -> send variable voltage to the light (to do the neat soft on-off effect).

Roll down the window, the same basic idea.

Cruise control is now completely integrated with the drive by wire system, which also ties into the ABS. It uses the 4 wheel sensors (there's another difference, your 124 has 3 ABS sensors, 2 front wheels and 1 in the differential) to calculate the vehicle speed. The speed regulation is via the electronic IP. About the only thing that is common is the fact that you move the control stalk on the column the same way for both models to effect the same functions.

The instrument cluster gauges are all stepper motors that read CAN bus messages to display their parameters.

Climate control is also tied into the body control system.

I won't even get into the DAS system. Suffice it to say that it must have the right RFID key signature to allow things to work. Otherwise you are not getting out of park and the IP gets no fuel.

Long story short, I think this is going to be too impractical to pursue.

Best thing to do is make sure your existing transmission is in top shape and the vacuum control system is properly adjusted and working properly, and enjoy the car and its 30 year old technology for what it is.

Or do a manual transmission swap.
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  #4  
Old 11-24-2014, 02:57 PM
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I was worried about the non lockup TC coming from my jeep that has one, but even without it the 300D is still getting 30mpg uphill at 80mph, so who cares. If the trans bites it I'll do a five speed swap.

As for an arduino TCM, it's probably possible to do a simple bump stick TCM, but you're going to miss out on a lot of safety integration and probably miss certain corner cases. Basically it would be driveable, but not by mere mortals. It will probably be more involved to drive than a standard clutch 5 speed.
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  #5  
Old 11-24-2014, 03:43 PM
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It's my understanding that under normal circumstances, the 722.6 doesn't even lock up until the engine reaches 3000 RPM. I have tried very gently accelerating at highway speeds and there's no noticeable "unlock" action. Normally the protocol is to unlock on throttle "tip in" or "tip out" to avoid a "harsh" movement. I can stimulate this on my truck by releasing the throttle followed by a gentle application. The tach will drop below cruise RPM, then rise above it and then fall back to cruise when lock up is re-established. However, I can't duplicate this with the car and since 3000 RPM is like 100 MPH, I can't really test my theory there.

This would seem to be an ungodly amount of work for the slight savings if any. If it was me, I'd rather just swap in a manual and really see some improvement.

Oh yeah, I forgot. The shifter on the .6 is all switches. The lever is just for parking lock (again, my understanding, not first hand knowledge) so not sure about shifting with a "ratchet" shifter. There may be someone out there that makes a manual valve body for these but it's not likely to be in the US.

Found some more info: http://www.atraonline.com/gears/2006/2006-04/2006-04_04.pdf

Also, since this transmission is used in Chargers, there may be some more info available on Charger driver/enthusiast forums.
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Last edited by KarTek; 11-24-2014 at 03:58 PM.
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  #6  
Old 11-24-2014, 07:49 PM
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The "modern" automatic trans has been around for about 60 years, get over it. ( and many of my cars / trucks are standard shift. )

As for the 722.6 being manual controlled, in the performance section someone worked with an universal automatic trans shift computer company ( Performance Products? ) developing software, it is way more complicated that you would expect and isn't like some trans where a few solenoids are easily triggered to make the shift or the only computer control is governor pressure / lockup . ( electronic shift rear drive Chrysler Torqueflight. )

As for the lockup, the 722.6 uses a modulated lock up signal varying lockup from 0 to 95% so you don't always feel the on / off bump. If 100% locked up, supposedly no fluid will flow through the converter / cooler / lube circuit with predictable results. Supposedly the lock up strategy works in lower gears and unlocks between shifts.
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  #7  
Old 11-24-2014, 07:57 PM
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Quote:
Originally Posted by jay_bob View Post

The W210 is completely computer controlled. Almost every body electrical device gets wired to a SAM module and the computer decides what to do.

The trans controller is stand alone from 96 to at 98 least and likely beyond. Look for a EGS module ( Electronic Gear Shift ) It is CAN bus but the messages could be generated with some sensors ( speed, load, RPM. . .) .

I'd go that route rather than developing a complete stand alone system.

96 didn't use a RFID key, 97 Got DASX RFID metal key , 98 got the smart key. The key talks to an anti theft module behind the instrument cluster that then talks to the engine computer, no anti theft is tied to the trans. When MB went to the trans after the 722.6, it got a computer in the pan that was tied to the anti theft system.
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  #8  
Old 11-24-2014, 09:07 PM
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Woah Woah Woah, wow.... So... In other words... It's a spaceship transmission lol. Well, I appreciate the in depth knowledge.
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  #9  
Old 11-25-2014, 01:49 AM
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More info about this inquiry is available on other boards... might search for some super turbo diesel forum and you'll find the info you're looking for

More custom related work is on there too... since you mentioned making some more power
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  #10  
Old 11-25-2014, 02:53 AM
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Quote:
Originally Posted by KarTek View Post
However, I can't duplicate this with the car and since 3000 RPM is like 100 MPH, I can't really test my theory there.
\\ Really? My 99 hits 3000 rpms at about 65 or 70 mph. Is something wrong with my car? I wish i could cruise at 80 at 2500 rpms like the vw does.
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  #11  
Old 11-25-2014, 08:21 AM
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Evan,
You have just made my day. I have been looking for a site that explains the shifting of the 722.6 and you have supplied it. I built a controller for a 4L80E (GM) some years back for a street rod. It wasn't that hard. A 722.6 would take a lot more "tuning" time, but doable. Just wish I wasn't so old now. Well, if I find one maybe I can get some help putting it in my 500 and will have fun making it shift the way I want it to shift.

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  #12  
Old 11-26-2014, 12:30 AM
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A 722.6 won't fit a 124 without widening the transmission tunnel. The 722.6 doesn't taper as much as the .3 and .4. You'll need shorter gears to overcome the 722.6 overdrive or you'll be cruising in the TC stall range.

Sixto
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  #13  
Old 11-26-2014, 07:11 PM
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Quote:
Originally Posted by biopete View Post
\\ Really? My 99 hits 3000 rpms at about 65 or 70 mph. Is something wrong with my car? I wish i could cruise at 80 at 2500 rpms like the vw does.
Does your tach look like this picture? If so, your transmission isn't going into 5th gear. Possibly the "Pepsi Syndrome" where the shifter is contaminated.

This shot was made when I had the selector in 4th.
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722.6 on OM603 TCU or ratchet shift?-imag0889.jpg  
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  #14  
Old 11-26-2014, 09:52 PM
Hears the voices
 
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The 4L80E and chrysler torqueflights as mentioned are quite simple trans in comparison. I know there are a few companies for the more complicated versions of those trans that make stand alone computers that are aftermarket. A few of the go fast jeep guys are starting to get their hands on paddleshift kits for the newer 5 and six speed autos.

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