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Converting from auto to manual trans

10K views 19 replies 8 participants last post by  Dave2302 
#1 ·
Hi guys,

I've been at it all day pulling a powertrain from a 2000 manual to transplant into a 1999 automatic.

I thought "hey, I'll pull the wire looms and transplant them too" but that is lining up to be a far more complicated job than actually pulling and re-installing the power train. Example, the wire loom from the shifter does not stay a virgin loom all the way to the electronic box but instead the loom is opened up in the passenger footwell. Part of it goes right and part of it disappears behind the plenum box and heads over to the driver side.

Question:

If I would install the power train of the manual into the 1999 without changing over the electronics, could I still expect the car to run? Does engine management and transmission management live in two separate places?
 
#16 ·
It is hard to understand why someone would want to convert from auto to manual? The other way, yes, but to manual? These cars are just serene with the auto box .... one of the best and SO smooth! (I have owned both types, by the way) It just doesn't make sense, to me .....

David

I totally agree. I have had the 4 speed that preceded the 5 speed in the same architecture and the 5 speed in 5 cars and wish I could have it in another brand I drive with a CVT.
It is tiptronic so you can play it as a manual to some degree.
Changing it out for a manual just doesn't seem warranted because of what the OP has noted. Electronics and clutches etc. are just too complicated to be worth the effort. Maybe better to sell both and buy one with a manual.
 
#3 ·
Hi,

I have done several Manual to Auto and vice versa conversions over many years.

Yes you do need a complete Donor Car, as its the most economical way to get all the bits you won't think of but will need and yes you need to swap the looms.

You also need to use SDS to recode Version Coding in various items such as ME ECU ABS / ESP and Dash Cluster or you will get problems.

Retain the recipient Cars ME ECU or you'll have Immobiliser Issues.

I agree with @DAJ 190 why oh why ???????????????

My V6 Car is a proper handful, will be even more so next year when the M113 V8 goes in, the last thing I want to do is take my hands off the wheel to shift a cog going through some of our West highland twisties very enthusiastically lol

Yes the ME and Trans are separate ECU's.

I installed Paddle Shift Steering Wheel on mine, awesome and no delays as it is hard wired to Shifter via a C Class Clockspring, (that has more wire cores) !!

HTH, Cheers Dave
 
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#4 ·
Dave,

Thank you for the reply. I have the donor car and the recipient side by side in my garage. The donor was involved in a small front end collision and the recipient's auto trans won't come out of limp mode. I've checked the fluid using the MB dip stick and a IR thermometer and also replaced the multi-pin plug, neither of which got it to come out of limp mode.


Let me ask you this- Looking at the wiring coming form the manual shifter and the clutch pedals switch I can tell that there are only two signals. The clutch switch with a brown/red with two black stripes which goes into the same pin on the ECU as the Auto car. Then, the shifter has the pink/grey (which I assume is for reverse) which one end goes to the headlight switch, the other goes to a pin in the ECU which is not installed in the auto car. You see where I'm going with this? It makes me think that if I install those wires, I'd be off to a good start.
 
#6 ·
It is way more complicated than that, ME ECU communicates with the TCU via the powertrain CAN Bus.

I am not mega familiar with 4 Cylinder Cars, are your cars Facelift or pre Facelift, are they 4 cylinder or 6 cylinder, it all makes a big difference.

as @Avel Du says @Turdo2 will know more, I would have to trawl WIS / EPC.

Both my own R170 and one of my Customers R170 are Post Facelift V6's, which I am now very familiar with ;)

Have you read the TCU in the Recipient Car to see what the fault codes are, might well be an easy fix.

Converting a Car one way or the other is not an easy task, nowhere near as simple as just swapping the Engine and Trans.

HTH, Cheers Dave
 
#8 ·
Dave,

Negative, I have not read for transmission codes on the automatic car, I don't have that in-depth of a code reader. It does, however; not have any regular engine codes according to my simple single-line OBD2 scanner.

Both cars are 4 cylinders, both are pre-facelift.

Since I had the manual car available to me it seemed cheaper to do the hardware swap. I would not have minded putting in the time. But now I think I'll scrap that idea. I'll wait to see what Mr. @Turdo2 has to say.
 
#11 ·
Hi,

Pre facelift still has Version Codings, for example the Dash needs to know Auto Or Manual, ME 2.0 (the old ME) still needs to know Manual or Auto, and I suspect ABS / ESP will, the older Cars will need more use of the HHT Win Emulator on SDS, where the later Cars some, (but not all) is done with DAS :wink:

AFAIK R171 is all DAS, R172 will likely be Xentry, and most likely need SCN Coding with online subscription....................

That's the beauty of the older MB's, no "big brother" necessary >:D

As OP's got both Cars, if he really wants to do it his easiest option is to swap all the Fuse Boxes, Wiring and Modules, Keys, Locks, RF Immo Module, Cluster, Pedal Box, Clutch Mech etc etc etc from the Donor, but he'll need to take half the Car apart to do this properly :surprise:

HTH,

Cheers Dave
 
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#13 ·
Hi @Happysaturday ,

Get someone with SDS to read your Trans .......................

Thing is this, (applies to all Cars), cheaper Code Readers only ever see a percentage of Codes in a percentage of Modules, the SDS will get to whatever the Fault is on any system on your Car, especially if there is a Limp Mode and / or a fault light on.

This is what always makes me smile when others come on a Forum or to my Workshop and say " The xyz light / message is showing, but my mate read it and says there is no fault codes" !!

This is not directed at you btw, more for anyone else reading who doesn't know that's benefit ...............

I'll say it again ................

Whatever the Car, if there is a fault light on, a fault message, or the system is in (proper*) limp mode, there will be a Fault Code ...................... It just needs the correct equipment to access it ;)

*NOTE:- A loss of Power does not always mean "Limp Mode"

In your particular case, if your trans is refusing to shift, then yes it (TCU) is in Limp Mode.

With this Trans, common problems are "Speed Sensor" or "TOT Sensor" Faults, which means a "Conductor Plate" change, (not too bad), also worth checking the TCU is not full of Oil, a leaky Connector can cause that, you've done the Connector, but did you remove the TCU and take off the cover to see if there is Oil present ? Washing the Circuit Board and Wiring Plug with proper Circuit Cleaner usually cures that, plus the TCU will need a reset on SDS for certain Limp Modes, (it has 2 limp modes, "Soft Limp" which just requires switch off Ignition and then restart, and "Hard Limp" which needs SDS or very good Generic machine to reset).

Can also be an ABS Wheel Speed sensor on some Cars, (not sure about Pre Facelift R170), or a Solenoid Fault, maybe Shifter Fault, and after that, there may be "Ratio Errors" ..............

Ratio Error, (assuming the Oil Level is correct, (Idling in P @ 80c), usually means the Trans is slipping and so needs a strip and rebuild, or a known good used unit, which must be one with identical 722.6xx number.
If replacing a Trans, don't forget to change the Converter with it, and also back flush the Trans Oil Cooler and Pipes with solvent ............... Parrafin, or one of the proprietary Trans Flushing Aerosols :)

I think that's about covered it lol ,

HTH,

Cheers Dave
 
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#14 ·
I'll keep it simple. You're car won't know any different. once you do the mechanical swap, just take the shifter control module out from the shifter assembly and leave it in P or N and then leave the harness under your console. You should be able to leave it in the other gears as well, but throttle response is slightly different. Take your transmission 13-pin connector and zip tie it up out of the way - dont mess with the TCU , leave it there and plugged in. Basically your car just thinks it's in Park.

Some C43 members on MBworld have done this as well as someone with a CLK430 that did the 6 speed swap. oh and me! :)

you WILL have to cut a bigger hole for the shifter. just take measurements from the parts car. Also make sure you carry over the driveshaft from the manual car.

and to improve your manual experience, get the rear end out of a CLK or E class with 2.82 gears - SOOO much nicer cruising at lower RPMs, and you can do 60 in 2nd gear.
 
#20 ·
Hi,

Decent Battery and decent Booster Pack is the answer to Tow Starts ;)

With the correct equipment and knowledge Electronics is not an issue, even more so on these "old skool" Benz platforms which don't need Online SCN Coding malarky.

Diff ratios on Auto can now be changed easily via at least one method that also changes other parameters such as Internal Trans Ratios, Shift points etc etc within EGS-52 ..................
I'm yet to try another method which (if it works) is even more readily available to anyone with SDS ;)

What @Turdo2 says about leaving parts in to fool it will work yes !!

However, IMHO it isn't the "correct" way to do it, especially when you actually have all the correct parts on hand in the Donor Vehicle.
It isn't something I would do ;)

I am very Anal about the way I work on my own and my Customers Cars.

Stripping that donor Vehicle is one of the best ways to gain immense knowledge about your own Car.

Cheers Dave
 
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