Friday, December 13, 2013

Mercedes W124 5 Speed Swap Guide

Mercedes Benz 300E/300CE/300TD 4 Speed Automatic to 5 Speed Manual Swap
List of Parts Needed:
103 030 1205 - Single Mass Flywheel
011 250 0903 - Clutch Disc 8.5"
004 250 3104 - Pressure Plate for 8.5" Clutch Disc
912004-008102 - Pressure Plate Screw washers - NOTE: You need six (6) of these
000912-008012 - Pressure plate screws - NOTE: You need six (6) of these
001 250 2415 - Throwout Bearing
115 980 0115 - Pilot Bearing
201 260 23 33 - Shift Linkage 5th/Reverse
201 260 22 33 - Shift Linkage 3rd/4th
201 260 21 33 - Shift Linkage 1st/2nd
000 994 29 60 - Shift Linkage end clips - NOTE: You need six (6) of these
201 540 1568 - Speedometer Cable 1490mm - Note: Some models already have this length of cable.                                        Remove from auto trans and install on 5 speed. They are interchangeable
001 295 6806 - Clutch Master Cylinder
201 290 0311 - Clutch slave cylinder
129 410 0601 - Front Driveshaft for COUPE
124 242 0501 - Transmission mount for 5 speed manual - NOTE: auto and manual use different mounts!
304017-010036 - Bellhousing Bolts - NOTE: You MAY reuse removed bellhousing bolts
304017-010035 - Bellhousing Bolts for starter - NOTE: You need two (2) of these. You MAY reuse bolts.
124 267 0097 - Shifter boot
B6 6 26 8109 - Gearshift Knob with leather boot
124 295 0513 - Clutch Line
203 997 3182 - Hose From Reservoir to Master Cylinder 270mm
124 683 0306 - Shifter Frame for Shift boot to center console wood (5 speed version)
XXX XXX XXXX - Shifter - NOTE: Will need corresponding shifter for particular transmission. They have                                    different shift patterns that the shifter assemblies are designed for
XXX XXX XXXX - Brake Fluid Reservoir - NOTE: The brake fluid reservoirs ON ALL W124 and W201 cars have a nipple on the side of the reservoir. Simply cut off the edge of that nipple and attach your hose to the master cylinder to this nipple.
XXX XXX XXXX - Brake/Clutch Pedal Assembly - NOTE: All W201 and W124 use the same pedals.
NOTE: There are some miscellaneous small parts that are not on the list. This is due to myself not wanting to take the time to find them and write them down. These omitted parts are small clips and attachments that are already used on the attachment parts to the automatic transmission.


Now that you have your parts, it's time to dig in

1) Remove exhaust system - from the Cat Converter back should be enough, but for mobility purposes, remove entire exhaust. 4 bolts at the exhaust manifolds, a few at the transmission, and 4 more exhaust hangers and you can drop the exhaust as one piece. Have a jack up front and have a helper "bench press" the rear of the exhaust while you remove exhaust hangers.

2) Remove the driveshaft - Note: The automatic transmission is around 25"-26" in length, while the manual is around 18"-19" in length. The difference is made up in the driveshaft. Notably, the front half. Because I had a front driveshaft off of a 84 190E, the spline was a smaller diameter than the one used on my 300CE, so the two drive shafts would not mate up.  I had the front half of my driveshaft cut and the front tip of the 190E drive shaft welded onto the front portion of my 300CE driveshaft. The shafts are the same diameter at their thickest point, but have different size yokes at where they meet at the transmission. The 190E yoke was retained and used with the transmission. I also had a tube machined and put inside of my new front driveshaft for extra strength. Driveshaft is neutral balanced.

3) Remove the automatic transmission. To get to the top two bolts, jack up the front edge of the oil pan slightly, with a 2x4 on the jack to prevent damage to make accessing the top two bolts easier. You will need a bunch of 3/8 extensions with a swivel  17mm socket. Make sure you have unbolted the torque converter from the flex plate and make sure you have unscrewed the speedo cable from the back of your cluster! Follow all cables from the transmission and unplug/remove them all.  Once all 17mm bolts are removed, find a 2x6 and place it on the jack and have a helper work the jack while you wiggle the transmission towards the rear of the car. Having a pry bar will make life easier.

4) Once transmission is removed, remove all unnecessary auto transmission cooler lines and all other parts associated with the auto transmission. 

5) Remove flex plate. While I was in there, I removed and replaced the rear main seal. Mine was slightly leaky, I don't know why as it was replaced by a shop a few years ago. I suppose instead of tapping it in gently, they whacked the thing in just to get it over with. I highly suggest doing your rear main. You're in there already, why skimp out on the extra $10 or so for the seal?

6) Install flywheel. Torque flywheel bolts to 30Nm followed by a 90 degree turn. The bolts used for the flywheel are stretch bolts. I do not know specs for reuse, so renew them! Better to be safe than to be sorry, these bolts are not expensive, don't skimp out and cause yourself problems.

7) Install your clutch

8) Install pressure plate and torque pressure plate bolts to 18 ft lb.

9) Fill your trans with fluid if you haven't done so already. Auto trans fluid is OKAY to use.

10) Install transmission - make sure you have a helper or a jack to lift the front edge of the oil pan to install the manual transmission. Either jack the transmission into place or put the trans on your stomach and "bench press" the transmission into place. Benching the transmission into place is far more accurate and much more effective. Have a helper if you need it.

11) Remove auto shifter and replace with manual shifter. Just for giggles, I replaced the factory rubber shift bushings with solid brass bushings. The result is a more solid shift. The auto shifter will be a PITA to get out, but if you pry away the covers, you will reveal all 4 10mm bolts. Those wires on the side of the shifter are now useless. They prevent the shifter from being shifting while the car is off or the brake pedal  pressed, simply move them off to the side. There is a difference between the shifter console wood pieces as the stick shift cars had a larger area cut out for the shift boot to be held in place. The automatic piece is fine, you'll just tuck the shift boot underneath and find a way to secure it to make it look good. I found gray leather and had a shift boot sewn together, than I upholstery glued it to the underside of the shift console wood. Looked good, looked factory and held together great.  

12) Line up the shifter arms by putting a small, but thick enough allen wrench into a slot already in the shifter assembly arms. This lines up the arms so the shifter can be moved side to side. Make sure the manual trans has all 3 of its arms in the upright position (neutral) and adjust the shifter rods to fit. This will ensure the shifter up top will be shifting solidly and smoothly. Because Mercedes decided to have aluminum shift rod ends that are incredibly fragile and mate them to steel rods (what were they thinking), I decided to make a beefier set that will outlast these destined to fail rod ends.

You can see the crappy MB design next to my beefy design.

Shift linkage ends are the exact same dimensions width wise and height wise, just with a little more effort put into the design.
Shifter Linkage Ends

14) Bleed your clutch/brakes. You will need a small diameter hose to attach to your right front brake caliper. Make
sure this hose is long enough to reach the right side of the transmission where the slave cylinder is. Just pump the brake and fill the reservoir. To bleed the clutch, you have to reverse bleed the system.

15) Put everything else back on and go for a drive. Hopefully you'll be good to go.

Now, if you wanted to put a 5 speed behind your HFM M104, there's going to be a little playing around to do. The M104 uses a small TDC magnet on the outer flywheel segments. You can use a standard M103 single mass flywheel, drill a hole in one of the segments and install the magnet
You can see the magnet on the top right timing segment.

The HFM M104's absolutely need this magnet in order to run. The CIS M103 and M104 do NOT need the magnet to run, they simply run using the segments themselves. 


Thanks for taking the time to read this. I hope it helps you, because I sure had a hard time putting everything together and figuring out what worked and what didn't. I did this swap some time in 2009 and the car is still driving great (with a new owner though). If you need any help or have any questions, feel free to leave a comment below or shoot me an email 
Take care,
(bsmuwk on benzworld and peachparts)


  1. this is amazing. what do you think a typical shop would charge for a swap job? (or, assuming you already have the 300TD estate, what would YOU charge?)

  2. i honestly have no clue what a shop would charge.

    I know that used parts sellers try to get around $1000 for the entire swap kit, from there it's just labor.

    I've done this swap on two of my cars (300CE with CIS M104 and a 300TD with OM603 ) and both took a couple hours to do.

    If i had to source, buy all the parts, custom fabricate some parts for a customer, it would be around $1800-$2300 USD - all depending on how smoothly things go with the individuals car.

  3. im looking to do a 5speed swap on my 1994 estate. i have a complete doner 300e. with everything swap over directly? i know ill need to install a magnet in the flywheel. but exctly how and where does it go?

    1. The only part that I don't believe will be direct bolt on will be the driveshaft. The sedan and wagon driveshafts are of different length the last time I checked. Don't take my word on that, you may just get lucky and they be of similar length.

      When you install the flywheel with the engine at TDC, you'll find the timing segment is beginning to line up with the crankshaft position sensor. It's at this point where yOU will want to install the magnet. It's done by drilling a hole into the segment, and is press fit. You'll actually be able to put your stock flywheel/ring gear next to the 5 speed flywheel and position the magnet that way (which is easiest as you're not spending time under the car).

  4. I feel like this might be a really really dumb question considering how people would kill for a SMF these days, but isn't there ANY other SMF from any of the other millions of cars that we could use instead of the unicorn that is the m103 single mass flywheel?

    P.s This is an amazing step by step guide and i love how easy it when its all written down. People like you really make life easy for us. Keep it up :D

    1. We could technically use the easily available Sprinter van flywheels, but the problem is with the timing tabs needed for the crank sensor. The sprinter flywheel doesn't have it.

      I'm still working on possibly finding a reasonable (not Mercedes) solution to flywheels for these old tanks. The problem is, there will probably be more flywheels running around than actual transmissions!

  5. Awesome thread, but still one thing is unclear for me..
    I have a 94 M104 3.2 with HFM and it was originally auto, but Im installing it in w201 manual and I got the M103 single mass fluwheel from scrappy and besides the magnet in the flywheel, the 3 timing tabs are longer on the m103 flywheel, than the m104 auto trans starter tooth wheel has. And also the overall diameter of the tabs is like 1mm smaller in total of the flywheel, but starter teeth are exact same diameter (aka the whole flywheel diameter).
    Could anyone aswer this one please?
    Thank you.

    1. Hey there,

      The sizing of the tabs will not matter as the system uses the magnet as a reference point. As long as the magnet is in the correct position, as referenced by the automatic flex plate - you'll be OK.

  6. Correction: the tabs are 4mm away from the crank sensor. Other mechanics tell me that its too far to operate the sensor.
    Is there different lenght sensors or something?

    1. No the stock sensor will pick up just fine. Just count teeth on the ring gear to position the sensor correctly and have it held in with a bit of epoxy as the automatic one is clipped in. The sensor will read correctly, you'll be able to fire the motor up without the transmission installed to check.

  7. Hi i love your post and am in the process of attempting a swap however i can not find any help...if you can please explain to me i have a 89 mercedes 190e 2.6.automatic and would like to swap from my donor car 1985 mercedes 190e 2.3 8v 5 speed trans into it however i was told i need a single mass flywheel and it is impossible to find there another way? And would this swap fit? Thank you for your time.

  8. Allen, I have W201 and planning on manual trans conversion. I am thinking about engine swap at same time. I know the work to do with M104 swap, but would like your opinion. 3.0 w/ mild camshaft or M104?

    1. i would 100% run the m104. so much more responsive with the 5 speed goodies behind it. you won't be disappointed with it over the m103.

  9. great. I will definitely plan on going with the M104. Thanks

  10. Found a 5-speed manual kit. Seller had removed from car and interested party never picked it up. It will be picked up by shipping company tomorrow. Found Donor e320 for engine and related components. Will rebuild M104 prior to installing.
    Also have source with several manual transmissions only. Will plan on building kits to sale. Hope to have kits to sale in near future.

  11. What is the p/n of 5 speed manual transmission you use/gear box? From which car can be donate year and model?

    best regards


  12. I have 300D 124 automatic 2.5D normaly aspirated(Non turbo), I like to swap to manual which manual transmission would be best for this engine.

  13. I have 300D 124 automatic 2.5D normaly aspirated(Non turbo), I like to swap to manual which manual transmission would be best for this engine.

  14. Hi I'm in Barcelona Spain, I've a 300ce 24v M104.980 with the 717.450 getrag dogleg, can I use the above clutch flywheel combination.
    Many thanks JP

  15. Is this process the same for my 1994 E320? I was assuming I needed a dual-mass flywheel to match the one off of my auto trans? Am about to go have a custom flywheel made up - perhaps you could shed light on if there is a cheaper solution than doing this...

    All other parts on my swap are coming from a donor 190E 2.6 (besides a driveshaft I'm having shortened).

    Thank you for you response and information - you an inspiration!!