MB four speed transmission
 

I have several 4 speed transmissions from PNP trips. I may also be able to put together a full W123 swap if someone wants one. Let me know if you are interested I figure $250 for a trans, $450 for a swap kit. If you are local I may even be able to do the swap, BUT, I will not garauntee the 1800-2200RPM vibe will not be there. I havent completely solved this on mine and I dont know anyone else who has either (300 turbo). If you want I can demonstrate the vibe on mine and see if it is something you can live with.

A driveshaft harmonic problem?

my firm belief is that there is a harmonic in the engine trans mount configuration that cant be solved by laymen. there's probably a good reason MB never put 4spds in 300 turbos. my guess is the NA need to operate at higher RPM since they do not have the power to even try to push the car at 1800RPM. as long as you are above 2000 RPM there is no vibe.

The very heavy 300d flywheel and the extra little mass around the flex joint at the tranny make it very very slight.

The 300 with a 240 fw and no extra mass at the flex vibes more but not enough to make me want an automatic!:P

me too, once you get used to the 3200RPM shift points the car is a blast to drive, heck it will even outrun a lot of the 4 banger ricers. I need to take the car out and do a 0-60 run. I know its pretty good with the gear I have now.

kit would include:

4spd transmission and bell
clutch
pressure plate
pressure plate bolts
240D flywheel
240D auto crossmember
flywheel bolts (used, manual recommends new but I reuse them once)
w123 full pedal assembly with master cylinder
slave cylinder
hyd line from master to reservior (these are generally rotten but the new part is $5
hyd line from master through floor
hyd line from floor to slave
W123 4sd shifter, rods and clips. I can shorten the rods if you want for the 300D
I will try to get a speedo cable, yours will not be correct length
wire harness from shifter (reverse lights, you will lose nuetral safety)
you will need to shorten the DS for a 300D. I can get one shortened for you for $75 plus cost of DS (should be around $20) it is recommended you do your own and balance the whole assembly together

I'd love to buy a kit! but I have a w126, if you can put together a complete kit for a 126, then you got a customer.

$450 is expensive without the necessary cut driveshaft.

Your firm belief is wrong. My car is living proof of that, NO vibration! :D

Nope. The difference between the euro non-turbo 617 and the turbo 617 as far as the drivetrain can tell, is nothing. The USA got all the turbo engines and you and I both know MB thinks power-hungry Americans are too stupid to drive a stick.

no one sells a kit with cut driveshaft and cut linkage for $450, thats what it is worth to me, if it doesnt sell then I wont spend the time to build one up.

I have seen 10 posts of people with vibes and one (yours) who have it fixed. the vibe is caused by a harmonic and it is on the engine side as it is consistent with RPM. if your cure was completely valid it would be repeatable. Please give us the recipe :)

I dont know MB's thinking you are correct. but are there turbo 4 speeds out there? and my turbo starts boosting around 1800 RPM, so there is a difference as a NA would not almost push the car at 1800 making it seem to this stupid american that I can run lower RPM. surely someone could have ordered one if they were available. In reality it shouldnt even be a problem if you shift at 3200 you wouldnt even know it was there

Im not sure there is any difference? if the pedals bolt in you should be fine. Take a few pictures under your dash up at the pedals and I will compare it to the W123 and W201 pedal sets I have to see if one of them will bolt up I remember asking the guy who did an SEC diesel conversion and he used the W123 pedal set, I dont remember if he had to modify it or not.

I think the pedals need very slight modification to fit the W126.

thanx, any info you have would be appreciated. my long term goal is to convert an SEC to a diesel 5spd

I have a factory Euro spec 1985 280SE with the four-speed. I would be willing to post some pics when I get a little time if anyone is interested. I am also considering selling the car.

Aaron

The w126 has an electric speedo. That is more difficult to get working with the 4 speed 240 trans.

yeah but I am surrounded by electrical engineers at my work, so Im pretty sure I can duplicate the pickup in the trans