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300TE Dogleg Transmission Guide

12K views 45 replies 14 participants last post by  bmfillman  
#1 · (Edited)
In late 2020 I inherited my dad's old 300TE Wagon. It's a 1993 M104.992 with good 'ol HFM injection.
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He couldn't use it anymore because the reverse gear went out on it. I have never enjoyed cars with two pedals anyway so this felt like a good opportunity to murder two birds with one rock. While researching which transmission to install, caltar2 on eBay recommended swapping in a 717.430 and changing the rear differential at the same time otherwise the gear ratios would be too sluggish and bogged down. For whatever reason, this sounded too daunting, so he recommended that if I wanted to keep the stock 2.65 diff, that a 717.450 with its 1:1 final gear ratio would be the best fit. As I learned more about the 717.450 I decided that it had enough of a "cool factor" to be worth whatever headache it took to install it in the 300TE. While in Qatar, I had an opportunity to drive a bus with a dogleg transmission and really enjoyed the convenient 2-3 shift. After a year of couch surfing and globe trotting and reading forums, I finally had a house with a garage where I could work on cars. Around the same time nelson_imports on eBay (great seller by the way) listed a 717.451 transmission "swap kit" from a 300SL that had just over 50K miles. This seemed like too good of a deal to pass up considering the low mileage and rarity.
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Once it arrived I got to work refurbishing the gear selector using Stretch's awesome guide on Peach Parts
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Only some minor differences between the dogleg gear selector and the others, but the EPC diagram was super helpful for reassembly. I did run into one issue with the upper pin getting jammed into place and so I had to force on it to the point where the shifter ball assembly was damaged. I ordered a refurbish kit from ECS and a couple weeks later after shaving the extra "wing" down on the ball assembly and installing the Delrin bushing kit that I got from 5thscaleracer, it was good to go.
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Next came the arduous process of removing the automatic transmission and associated bits. For the most part I followed Allen Kroliczek's guide on Artisan Motors
It is a great guide but not all encompassing. He mentions having a custom front prop shaft built for him, I have yet to find a shop that will do that for me, instead I'm still trying to find a stock one that will fit. His description of removing the automatic transmission relies on having a second person, but it is possible to do solo as well. Also if you don't know what unbolting the torque converter from the flex plate is, like me, then attached is a picture.
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There is a black plastic panel near the bell housing that if you pop off will reveal the front side of the ring gear. As you rotate the engine you will reveal six bolts that you need to remove. Aside from these, you have to remove the auto tranny dipstick which in my case had a seized bolt from hell attached to the valve cover that I had to dremel off, two plugs that I have no idea what they do, the shifter linkage, the two large wire plugs that route into the cabin, the mechanical speedometer, the vacuum line and kickdown cable assembly, and the bell housing bolts. Pictured is the bolt from hell's location.
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And I think that's it, probably not, but as long as you're slow and methodical you should be good. In my case I wasn't and I was the only one removing the damn thing so as I ripped it off, the oil pressure sender snapped as the engine ricocheted back into place.
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Installing a new rear main seal is definitely the way to go
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As far as flywheel bolts are concerned, Mercedes will tell you that one of these won't fit but I think both are just fine, they're listed as compatible on the EPC I use (this may not be true, use at your own risk).
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#2 · (Edited)
The Artisan guide glosses over how to install the timing magnet from the ring gear to the DMF, it's a PITA and even though the timing tabs are physically a different size, it has to go in the exact same place with reference to the teeth! A setup like this ensure that your measurements are accurate to the nearest foot so if you have a better setup definitely use it!
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The Artisan guide also doesn't go over how you can sketchily check if your setup will run, by grounding the bell housing, bolting in the starter and just going for it. Don't do it yet though!
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First, grab the tranny wiring harness and jump the purple wires. But how will you know which wires are purple? Jump it as pictured below before altering your harness permanently if you want. I also jumped the wires on the screw on plug. Don't ask me what that does, I have no idea. Later on I ran it without those jumped and it ran fine.
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Jumping the purple wires to my understanding bypasses the neutral safety switch will allows the starter to activate.
I'm not sure how to upload a video but rest assured the first time I started the car it misfired so badly that a ball of fire escaped the manifold and almost burned everything to the ground. I quickly removed the DMF and found the culprit, can you guess what it was?
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That's right, it was the damn crank position sensor. The Artisan guide won't tell you this but if the transmission you're installing is from a non HFM M104, your HFM M104 crank position sensor sticks a couple fractions of an inch too far out. Above you can see how the DMF legitimately sheared the CPS. It was just the tip though. I installed the timing magnet back onto the ring gear in a panic to make sure I didn't fry the engine. It ran just fine, which doesn't mean anything but did allow me to breathe again. After a new CPS came in the mail, I put a small rubber O-ring between the case and the position sensor and this gave it the proper spacing to allow the new DMF to run.
 
#3 · (Edited)
Where am I in the process now? Well I realized that the 717.451 doesn't have a mechanical speedometer output and that Mercedes no longer sells the rear case and speedometer gearing to be able to convert a 717.451 into a 717.450, so I recently purchased some 717.450s in Germany (shout out eBay Kleinanzeigen) to smuggle back into the United States with me. I am also waiting on a Single Mass Flywheel conversion kit from Rennsport to be delivered because I've decided to put something that can be resurfaced and last longer into this car. I am also going to try to locate a stock 717.430 front prop shaft to see if it's compatible, otherwise I'll have to have a custom front prop shaft made up. Edit: Keep reading, I ended up completing the swap with one of the 717.450s.
 
#11 · (Edited)
This is the coolest thing I've seen in a while. I've been itching to get a wagon myself since the arrival of my son, but the rarity of manual 123/124 wagons here in the US has put a damper on my desire to get one.

I'm no stranger to swapping in manuals, as I've done my '96 F350, going from the E4OD to a ZF5, and my Durango going from the horrible auto to an NV3500. Were parts more available domestically in salvage yards and such, I'd be all over it!
 
#12 ·
This is the coolest thing I've seen in a while. I've been itching to get a wagon myself since the arrival of my son, but the rarity of manual 123/124 wagons here in the US has put a damper on my desire to get one.

I'm not strangers to swapping in manuals, as I've done my '96 F350, going from the E4OD to a ZF5, and my Durango going from the horrible auto to an NV3500. Were parts more available domestically in salvage yards and such, I'd be all over it!
Yeah definitely a PITA insofar as finding parts, but definitely fun breaking things and learning! For example, when I removed the automatic gear selector I was stunned to silence for a couple minutes to find that the gear selector has a mechanical lockout for the brake pedal. Perhaps this is commonplace but I just thought it was the coolest damn thing that the gears can't be shifted even if the car is off, unless the brake pedal is actuated. Have you thought about looking to our neighbors in the north? They may have gotten better pickings for manual wagons.
 
#13 ·
Other bits and pieces I've knocked out while waiting for parts include:
Cleaning up the wiring a little bit as pictured below.
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Here you can see the purple NSS jumped as close to the plug as I could go, and the reverse light wires extended to then be routed through the center console to the reverse light switch on the gear selector.
Installing a new center support bearing on the prop shaft, which, if it's never been done before is definitely a good idea.
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Installing the gear selector
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I went with Zebrano to match the rest of the interior, my main advice with the gear selector is to be super slow and methodical moving wires and cables out of the way while shimmying it in there. There is an insanely little amount of clearance and you'll have to play with multiple angles to make sure nothing gets pinched. I thought I had it in perfect but then I noticed when I tried to turn the key in the ignition later it wouldn't budge, and it was because I had pinched the ignition lockout cable under the corner of the gear selector and tightened it down.

Here is everything mocked up including a new zebrano steering wheel that I got from woodandcarbonworks on eBay (Lordy those Turks know how to make a fine wooden steering wheel) and a beautifully refurbished center console that I got from w124belgiumm on eBay.
There is a really good guide for steering wheel removal on Pelican Parts if you need one.

All this wood may detract from the original understated feel of the cabin, but hey, I like it, and money can't buy good taste ;)
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I also installed the pedal assembly so I can pretend I'm driving it as it sits on jack stands for months on end.
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Process wasn't too complicated, just take some before pictures so that the brake pedal spring location isn't lost on reassembly. The top two mounting bracket bolts are also a PITA to access, so have several swivels and extensions for your ratchets. Also, the bolts from the 300SL were 11MM and the bolts on the 300TE were 10MM so I almost stripped them out, make sure you have the right size socket.
 
#21 ·
Long time no see y'all, guess I should give everyone an update! Came back from Germany about a month ago and got cracking on the transmission posthaste. First thing I should start off with is that I left key pieces of info on pulling the automatic transmission. First off, there is not one but two vacuum lines that need to be removed from the car. The first is the obvious green one that connected to the small plastic bit to the right of the two large yellow clips in the below picture.
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The second one is a slightly less obvious black one that connects to the plastic air intake plenum pictured below.
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In both cases I used some rubber vacuum line caps that I picked up at the local O'Reilly's and then cinched them down a little extra with some plastic zip ties. The only remaining relic from the auto tranny was a small black plug on the right side of the transmission tunnel which I sort of just pushed back into its recession and forgot about, since I couldn't find anywhere on the manual transmission to plug it in. Now that everything was accounted for, I installed a slightly longer mechanical speedometer cable that came in the 300CE-24 and was designed for the manual transmission. I believe that the automatic one may have worked fine, as it was only slightly longer than the original but your results may vary. Next, I prepped the 717.450 I picked up in Germany by ensuring the fluid was completely drained, and installing a new magnetic drain bolt, fill bolt, rear transmission mount, clutch release or "throwout" bearing, and giving it a good clean. I then installed a new FTE slave cylinder, lubed up the release fork and center spline and started bending a new slave cylinder hard line in place.
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For the most part I used a plain jane tubing bender and tried to model the bends off the original slave cylinder hard line, which had stripped horribly. No kidding, the bolt turned into a circle on the old fitting. Here's the new one compared to old. Also pictured, the two types of pipe bender I used.
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I also pulled the pedal assembly that I had installed earlier in the year and disassembled it to install the new brake fluid reservoir to master cylinder hose (which is a complete redesign from the old rubber style, and can be seen in the picture of the first vacuum line cap) as well as a new FTE master cylinder. Pay particularly close attention when reassembling the master cylinder assembly, as the black hook thing has to go back in behind the master cylinder and cannot be removed completely, despite the whole clutch release electric impulse assembly being useless in my application.
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#22 ·
Next, I attempted to press fit the supplied pilot bearing into the Rennsport single mass flywheel that they sent and was surprised to see that it freely slid through. They recommended a pilot bearing from Mercedes, part number A0189812510, so I ordered one and successfully pressed it in.
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Now I had to ensure that the timing magnet placement on the SMF would be compatible with my HFM magnet sensor spacer. Stock flywheel bolts do not work with the Rennsport SMF, and they recommend 12.9 socket caps which I purchased from Belmetric for quite a reasonable price. I used Belmetrics M10x1.0 x 25 mm which worked perfectly for me but do note that they are no longer torque to yield, and are therefore not factory and as such install at your own risk! Plenty of red thread locker and 40 NM followed by 80 NM was the torque spec I used and we're holding steady for 100 miles now. After the test crank (as a reminder, the engine can be started with just the flywheel, grounding bell housing bolt and starter bolted in but it is sketchy), I installed the friction disc and pressure plate.
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I then installed the transmission with the help of my girlfriend (mostly me screaming bad words and her cowering in fear with a flashlight).
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I then bled the brakes with my new Motive powerbleeder to cycle out what I can only assume was 30 year old brake fluid, cut the nipple on the brake reservoir and plumbed/bled the slave cylinder with the help of an assistant.
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Reminder that brake fluid is caustic shit and is horrible for your paint.
Once the clutch was properly bled, I filled the transmission fluid with Dexron 3 with a little bottle mount pump dealio I purchased at O'Reilly's.
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The issue now was that I couldn't tighten the fill bolt properly with the horrible clearance, but FCP euro sells the perfect M14 wrench tool to remedy this issue.


Once this was all bolted down, and the rear tranny mount was installed I "drove" the car to see if the clutch was properly engaging and disengaging, to check for leaks, to make sure the mechanical speedometer cable was properly installed, and to make sure the output shaft would spin. Here is a picture of the proper hose/cable orientation by the way.
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#44 ·
Next, I attempted to press fit the supplied pilot bearing into the Rennsport single mass flywheel that they sent and was surprised to see that it freely slid through. They recommended a pilot bearing from Mercedes, part number A0189812510, so I ordered one and successfully pressed it in. View attachment 2784169
Now I had to ensure that the timing magnet placement on the SMF would be compatible with my HFM magnet sensor spacer. Stock flywheel bolts do not work with the Rennsport SMF, and they recommend 12.9 socket caps which I purchased from Belmetric for quite a reasonable price. I used Belmetrics M10x1.0 x 25 mm which worked perfectly for me but do note that they are no longer torque to yield, and are therefore not factory and as such install at your own risk! Plenty of red thread locker and 40 NM followed by 80 NM was the torque spec I used and we're holding steady for 100 miles now. After the test crank (as a reminder, the engine can be started with just the flywheel, grounding bell housing bolt and starter bolted in but it is sketchy), I installed the friction disc and pressure plate. View attachment 2784171
I then installed the transmission with the help of my girlfriend (mostly me screaming bad words and her cowering in fear with a flashlight).
View attachment 2784172
I then bled the brakes with my new Motive powerbleeder to cycle out what I can only assume was 30 year old brake fluid, cut the nipple on the brake reservoir and plumbed/bled the slave cylinder with the help of an assistant. View attachment 2784173
Reminder that brake fluid is caustic shit and is horrible for your paint.
Once the clutch was properly bled, I filled the transmission fluid with Dexron 3 with a little bottle mount pump dealio I purchased at O'Reilly's. View attachment 2784174
The issue now was that I couldn't tighten the fill bolt properly with the horrible clearance, but FCP euro sells the perfect M14 wrench tool to remedy this issue.


Once this was all bolted down, and the rear tranny mount was installed I "drove" the car to see if the clutch was properly engaging and disengaging, to check for leaks, to make sure the mechanical speedometer cable was properly installed, and to make sure the output shaft would spin. Here is a picture of the proper hose/cable orientation by the way.
View attachment 2784175
Sorry to be a little late to the party but in regards to the RENNSPORT SMF what clutch setup did you end up using?
 
#23 ·
Wrapping things up, I had to shorten each gear selector rod by 2 3/8 inches which I had a friend who was good with a welder do for some beer, and they turned out okay!
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Slapped some new Febi gear selector links on there, the rest of the Delrin bushings and it was time to install the prop shaft which I had gotten resized and rebuilt by Pickard Gelenkwelen while in Germany.
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Thankfully, numerous measurements paid off and it fit beautifully. Next I installed the center exhaust hangar, new rubber exhaust hangars, the heat shielding, the O2 sensor, the manual transmission sized exhaust transmission bracket and finally the exhaust.
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She lives!! The SMF is a pain to get used to, and I've lightly toasted the clutch a couple of times but damn is this thing fun to drive! Just waiting on a custom shifter boot bracket.

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Here was all the new wood installed while the driver seat was out.

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#25 ·
Yeah I don't mind the single mass but I think next time I change the friction disc I may switch back to dual mass. It could be the lightweight kit from Rennsport (or maybe I'm not as good as I thought at driving manual) but it's a steep learning curve driving it! Is it easy to drive the 404?
 
#29 ·
Just buttoning up another odd and end, big thanks to @TheWestminsterClub for his suggestion about using two 3/8 inch FIP brass pipe caps to plug the auto tranny fluid cooler that sits next to the radiator. Should stop debris from getting into that part of the radiator, and maybe even make it viable to convert the car back to an automatic once the resale value reaches the aluminum Gullwing levels ;)

Here is where the auto transmission fluid cooler lines used to screw into
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And here is the part, easily found at Home Depot.
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Also here's a bonus picture of the car with the euro headlights (minus the euro wipers) installed.
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#30 ·
Nothing should be SAE, FIP or otherwise on this car. I'm surprised the cap fit.

But a manual wagon would be nice.
 
#32 ·
Did some finishing touches on the manual swap, the under dash panel didn't accommodate the third pedal as it was. Luckily, Mercedes left a trace on the plastic that can be cut to make it "factory."
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Here it is pictured, just cut along the dotted line!
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Then the rest of the drivers side panels were installed.
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I also came up with a temporary solution to the gear selector problem. If you'll recall, the stock gear selector cutout for automatics is larger than manuals and as such, there is no practical way to fit a manual shifter boot into the automatic hole. My solution was to stretch a universal leather boot over the plastic trim panel on the old automatic shifter, and rest it in place.
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Next challenge will be to find a way to secure it in place, maybe with some sort of clip addition on the bottom.

The car has been holding up well, I've been daily driving it, but noticed that the fuel mileage is pretty abysmal and who knows when the ignition system was worked on last, so I've got some FCP euro goodies coming in the mail for a total refresh.
 
#33 ·
Wow! Love the manual swap, it is actually almost the exact swap I was looking to make. A few questions:

Why did you have to shorten the gear selector rods?

Also which weight flywheel did you go with? If you went with the lighter weight I am curious if the heavier one is a better option.

What is your diff ratio?

I think I recognize your CARpet from ebay selling a 717.450. I wasn't planning on doing the swap until next winter when I have some time, but I just might have to grab that if the wife is cool with it just sitting in the garage for 9 months!
 
#34 ·
Wow! Love the manual swap, it is actually almost the exact swap I was looking to make. A few questions:

Why did you have to shorten the gear selector rods?

Also which weight flywheel did you go with? If you went with the lighter weight I am curious if the heavier one is a better option.

What is your diff ratio?

I think I recognize your CARpet from ebay selling a 717.450. I wasn't planning on doing the swap until next winter when I have some time, but I just might have to grab that if the wife is cool with it just sitting in the garage for 9 months!
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#37 ·
I wish I had a baseline rubber bushing to compare them to but I never had rubber bushings installed on the car as a manual. Comparing it to other manuals I have, the gear placement feels a lot more assertive and reassuring. The shifts feel crisp maybe even a little tight, and there's never any question about whether I'm in gear or not. One downside would maybe be that there's not a lot of forgiveness if you're going for a quick shift and miss the "gate" by a hair, the car simply won't let you. But long story short I love the delrin! Took a little extra drilling to get the size perfect, but well worth it.
 
#38 ·
Commonly applied in the w201s way back.
 
#43 ·
Sorry about the late reply, I purchased them in the original "swap kit" from nelson_imports on eBay. They were out of a 300SL and I guess because of the long hood on those cars, were way too long for the 300TE so had to be cut down to size. I looked all over the place for original Mercedes shift rods and couldn't find them anywhere. Good luck on your search!