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Need help find alternatives manual transmission for OM617

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3.6K views 3 replies 4 participants last post by  PlaneCrazy  
T
#1 ·
Hi everyone. I need help to choose alternative manual transimission.

Here's my condition:

Long story short; because engine problem, I have swapped my 1978 280 (euro spec) to OM617 turbodiesel w/o the turbo (USA spec). So I have a W123 with OM617 with 280 transmission and 280 rear differential. the engine seems doesn't run to its maximum potential. My top speed is around 40mph which is painfully slooww.
I've change the rear differential with W115 200, now it's runs so much better. My acceleration and top speed is improved greatly yet still very slow (now I can do 70mph++).

Should I change the transmission as well? if I should, which transmission will suits it better?

The problem is, I live in Indonesia and there's very limited choice of W123 and /8 parts.
available option for manual transmission and rear differential are only 200/230/230E, 280/280E, and 240D. all are in euro-spec.

with thanks,
Tom
 
S
#2 ·
the transmission ratios doesnt differ, 40mph sounds wierd, despite differential to be honest.

what ratio is the differential you swapped from?
a w115 200 gives a lot of revs, and that differential (probalby 3.92 or 4.08 is not optimal for a healthy om617 NA.

i would to be honest suggest you swap back, and fix the engine, the problem is much likely nothing with the transmission nor differential, but the engine that has problems.
Does it get fuel? is the pump correctly timed, (does it sound like a diesel should, does it smoke white or black?)

a 4.08 differential will affect your mileage, engine durability, and more
i would suggest swapping back, absolutely, (to a 3.69 or 3.58 you probably had earlier, or even lower, 3.46 that the engine had stock..

--
Al the fourspeed manual transmissions is about the same, the fourth gear is 1.1, any gearbox change wont affect your car at al.
Concentrate on the engine, the om617 even in NA version packs some punch.
 
#3 ·
You have throttle or fuel issues, not drivetrain. Make sure the injection pump lever is reaching the maximum stop when the pedal is pressed to the floor.
 
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#4 · (Edited)
Even a stock NA 240D can reach 90 MPH on a 3.69 diff and direct drive. I second swampmonkey's advice, your engine is far from healthy.
 
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