I found a fantastic description of a automatic to manual conversion from a few years ago that inspired me to do the same to my 300TDT.

Auto -> Manual Transmission Conversion Has Begun.

I wanted to know if the 115 body four speed manual transmission (115 261 16 18/ 115 261 25 01) will fit a 300TDT motor. It looks very much like the early type 3 piece trans fround in the 123 cars with the 4 cylinder engine.

Yes, they're the same.

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Never a dull moment at Berry Hill Farm.

Thanks R Leo, looking over your original posting, I now see that the question came up (somewhere in its 18 pages).

I got the tranny, support, drive shaft, pedals, shifter etc, and as soon as the weather clears up a bit I will start on the conversion!

BTW what is a good oil to use in the manuals, I have been told ATF type A, which I have neever seen, or 30W nondetergent oil.

Will the 4-speed hold up to the bigger engine? That would make it tempting to put a 300D and appropriate rearend ratio into my 220D...

My 220D FSM just lists ATF as the fluid for both automatic and manual trannies, doesn't state a different type for either. I will soon be changing the oil in my 4-speed, and would also be interested if there is a preferred brand (is there synthetic?) to put in.

I use Redline MT. It looks just like ATF to me but is more expensive and harder to find


ROFLMAO! Mine has done fine for 30,000+ miles.
FWIW (and this has been covered over and over in this forum) the 4-speed manual tranny with the cast iron housing is tres stout! Far, far bigger gears than any Chevy 4-speed. Anyway, the turbo 5-cylinder ain't no monster engine. On a REALLY good day they only make about 90 hp and 125lb/ft of torque at the rear wheels.

Still in doubt? Check this out: 4-speed manual / OM617 in G-wagen

The first pic is the venerable 711.xxx cast-iron tranny bolted to the back of a 5-cylinder n/a diesel and installed in a G-wagen...from the factory. The following shots are the conversion to a 5-speed which, in that vintage is the pratcically same 4-speed box with a different tailpiece installed.

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Never a dull moment at Berry Hill Farm.