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M103 5 Speed Swap

14K views 56 replies 14 participants last post by  gatorblue92 
#1 ·
Well it looks like the transmission in my 91 300TE has failed. On the way to work this morning I was stopped at a red light and went to go when the light turned and the car didn't move. No odd noises or warnings at all. I tried all gears and nothing :(

I was planning on a 5 speed swap at some point but not this soon. Has anyone who has completed this swap got ant tips? I have done a manual swap in a W123 but my car has ASR so its a bit more involved. I can't find a clutch on any of the usual parts suppliers. Is this a dealer only item?
 
#3 ·
I've never seen a M103 powered 124 with ASR. Have you been able to illuminate the ASR light in the past? I would think that the transmission, clutch, flywheel, driveshaft and all associated parts from the parted out 87 car would bolt right in.
I'll second Jim here.

Anyway, IIRC, you're the one that was parting out that white 5 speed? Everything from that car will swap directly over to your 300TE, outside of the driveshaft. I haven't dabbled in finding a stock MB shaft that will fit in place when I swapped wagons over - I bring a local shop the pieces and length I want and they'll weld up and balance the shaft for me for $100 and a couple days turn around.
 
#4 · (Edited)
When I did the swap it helped to have both the donor and receiving vehicles side by side for the duration of the swap. Kept me organized and on track. Are you going to keep the 300te diff or swap in the 300e ratio?

Order a delrin shifter bushing kit from the guy on 190rev (i posted the link in your previous thread). Its worth every penny.

Have lots of socket extensions on hand of the top 2 bolts holding the transmission to the block. About 4 feet should do it with a wobble join on the end. Mityvac makes bleeding the slave cyl much easier.

Remember to wire a cruise control switch onto the clutch pedal. I forgot to do that. First time I pressed the clutch with CC switched on, the revs jumped to 6k in an instant before I realized what was going on and hit cancel.

This is a good time to order up a new speedo cable, trans mount, flex disks, engine mounts (maybe), slave cyl (master cyl usually lasts forever), new hose from brake reservoir to master cyl, the usual clutch kit, exhaust hangers, DS center support, rear main seal.

Put new oil in the transmission before you install it in the car.
 
#5 ·
All of the "non consumables" from the 87 are going into the 91 but I'm replacing the clutch parts and driveshaft bits since they are 10 years old and need replacing. I'm fairly certain the engine mounts are only a year or two old so I might skip them but the rear main seal is a good point. I hadn't included that on my parts list. Do you know if the flywheel bolts are stretch bolts and need replacing each time like they are on the W123?

I've never seen a M103 powered 124 with ASR. Have you been able to illuminate the ASR light in the past? I would think that the transmission, clutch, flywheel, driveshaft and all associated parts from the parted out 87 car would bolt right in.
Yes it has ASR and its fully functional. The light on the dash comes on when you first start the car and I have had it come on a few times while driving in the snow. I believe 91 was the first year for both ASR and ASD. The car has the ASR ABS pump and the snow chain switch too so if someone added it after the fact they did an excellent job.
 
#7 ·
I had to look that up...

Mercedes nomenclature is sometimes quite interesting. I come from the VW world, where the term stretch bolt implies torque to yield fasteners (think cyl head bolts), which always need to be replaced after use. I suspect that MB uses bolts that incorporate an elastic stretch into their clamping ability, but mostly aren't pushing up against the elastic limits under normal torque specs; hence the dimensional allowances for acceptable stretch for serviceable fasteners.

http://www.w124-zone.com/downloads/MB CD/W124/w124CD1/Program/Engine/103/03-4100.pdf
 
#8 ·
I found a Sachs clutch kit on Rock Auto which I ordered using a gift card I got for Christmas last year. I still need to source the master and slave cylinder, a new line from the brake master to the clutch master, rear main seal and new flex disks. The bolts appear to still be in spec but I might replace them anyway depending on the cost. The single mass flywheel is going on Monday to get re-surfaced since it looks like it needs to be done. I might try to start pulling the auto out this week since I need to get the car back on the road sooner rather than later since the 400E needs work too :/
 
#9 · (Edited)
You are correct no warning if the auto tranny goes lost my reverse while parked.. Luckily i found a 5 speed diesel car again to drive around in the meantime..
 
#11 ·
Yeah that clutch line seems to be a dealer only item.

I'm seeing two different real main seal sizes. I'm assuming I want the repair one so it will cover any crank wear.

Made some progress and by progress I mean I got the shell from my 87 300E out of the garage and hauled off to the crusher so I have a place to work on the wagon.
 
#12 ·
I don't know about the M103, I only saw 1 size for the OM603 RMS. I assume its the same. Have some honda bond or permatex grey handy for reinstalling the cover around the RMS.

I hope you pulled everything you needed off the old shell :eek

What are the diff ratios on the wagon and sedan? Are you keeping the wagon diff?
 
#13 ·
Yes I'm keeping the wagon diff since its ASR and the 300E wasn't. I do have the complete rear subframe so if for some reason I do need the diff I have it. Its a stock auto 300E diff from 87 since that car was also a 5 speed swapped car. The 300E was basically just the shell and the rejected interior bits from my other cars. I think there was at least two complete (albeit trashed) interiors in there so in addition to getting rid of the shell I also cleaned a bit of junk out of my basement.

This afternoon I picked up the flywheel from the machine shop where I had it re-surfaced. I also ordered the clutch hose from the dealer and it was a grand total of $12.
 
#18 ·
I know the ASR is somehow connected to the ABS system and the diff may in fact be the same between the ASR and non ASR cars. As of now I'm planning on keeping the wagon diff in place unless there is some compelling reason to swap it. I was under the impression that the ASR and ASD systems were nearly identical but just had different applications.
 
#19 ·
yeah, if what that flyer says is true, i was wrong bout ASR, its not just a trhottle limiter, its also some per wheel braking control.

that means it must have some additional brake modulation... as the standard ABS can only release brake pressure, not increase it.
 
#20 ·
Since you're re-gearing the drivetrain, I would pay close attention to matching the trans gear spread, with that of the diff ratio, wheel diameter and the torque curve of the engine.

Try punching all those drivetrain specs into this gear calculator, and then compare the two diff ratios side-by-side.

MFactory® Competition Products - Gear Calculator

Given the torque curve of the M103, you may find that a taller diff ratio will have you downshifting constantly from fifth whenever reaching a hill. A turbodiesel can probably take the taller gears, since it produces peak torque much lower in the RPM range. For the purposes of establishing a fixed baseline vehicle speed to rpm set point when re-gearing the vans I work on, we often try to focus on achieving a gearset/wheel diameter that allows the vehicle to cruise 70mph at no more than 3000rpms
 
#23 · (Edited)
#24 ·
when i did a swap on my '88 190d the local hose and pipe shop silver soldered in a piece of braided stainless over teflon for the flexy on the line that goes over the transmission for the clutch..30.00$ 25 minute wait. leave the 3.27. for sure don't use the 3.07 or you'll be hatin life shifting between 2nd-3rd all the time in town and never using 5th till 75MPH +.
 
#25 ·
The 5 speed donor car had the 3.07 diff according to the numbers above and I thought it was just fine. I drove it for 18 months and 22k miles.

Got my Sachs clutch kit in yesterday. Still waiting on the hydraulic bits and the rear main seal parts.
 
#26 ·
Got the automatic out yesterday afternoon. It's a lot heavier than the manual was. Someone in the past had stripped out one of the flexdisk bolts so I had to grind it off. Not fun but it's off. Next up is pulling the auto flexplate and changing out the rear main seal. All of the parts should be in by the end of the week so hopefully I will have it back on the road by the end of next weekend.
 
#30 ·
Did a little bit of work last night which included removing the auto flexplate and the shifter assembly. I'm in a bit of a holding pattern right now waiting on parts. The rear main seal didn't show up with the rest of my parts order so I may end up getting one from the dealer. Not happy but I need to get the car back on the road.

Does anyone know offhand which wires you need to jump on the NSS? They are different in this car than the donor (go figure)
 
#31 ·
Had an unexpected day off work today due to a water main break by my office so I put my time to good use.

I pretty much finished everything inside the car including the wiring for the reverse lights and bypassing the neutral safety switch along with all of the plumbing for the clutch. I'm pretty pleased with my progress but a bit annoyed that I'm waiting until next Monday for the order I placed from the house of autos in Arizona... Anyway on with some pictures including some from my prior steps.

Got the Flywheel back.



Discovered the source of my driveline vibration :eek:



Transmission is out.



Getting somewhere.







All done inside the car.



Another annoyance I ran into was a stripped out bolt on the exhaust downpipe to manifold connection. I had to remove the exhaust manifolds to get enough room to get in there and grind the bolt head off. Thankfully I have another set of manifolds so I decided to paint them while they were off.

 
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