w116 300sd trans fluid leak/ change to manual trans
 

Haven't put it on the lift yet. I assume it's the front seal? does the rear seal ever leak? or the torque converter itself??

Then again, before doing all that work.... it's pretty easy to find complete 602 engines with manual trans set-ups around here. I'm thinking to do that swap, anyone ever done it and do you need to make new motor mount
points in the chassis? or I could install 5-speed off a m110 or 617 N/A...

I would find the leak and fix it, lot easier then doing a manual swap....I don't know why everyone wants a manual trans...I loved mine on flat ground and no traffic around....but getting up a hill, parking on a hill or sitting in traffic I hated it....I have the arthritic knee to prove how much I hated it :P

let's face it, the 617 turbo is nice, but really kinda ancient and consumes lots of diesel without giving much power. the newer 602 is much better and fits. so... why not get rid of that shaky horrible 617 and upgrade?
even with an automatic it'd be better. then again, automatic transmissions waste energy into heat and you have no control over your gears. I don't like that.

Sorry, all OM60X engines and the M110 have the starter on the driver's-side, where the OM61X series has it on the passenger's-side. You'll need to find a transmission off of an OM61X to do the conversion...

Go for it! Someone recently had a thread here about converting his W116 'SD -- he used a 240D donor and said that everything (including the driveshaft) fit right in!

He wants to swap the transmission and engine from a later model.

I'm sure it can be done, but I'm not sure of the particulars. I like the idea.

interesting! so all parts to make it manual from the 240d fit the sd, pedal, shifter etc etc? did that person change the diff?
in that case I'd go for that, as my 617 is in good shape..
then again, I really love the 602. even non turbo it's a bad ass engine.

Indeed so. off a w124 with 602 turbo and auto trans or N/A with manual trans...

then again if I stumble upon a rusted out AMG 280se, I'll scrap that, use all the AMG parts incl 5-speed and have a bad ass 300sd!!

If you want to keep the 617, you can use a four (or rare five speed) from a 240D or a Euro 300D.

Here's the thread. It's actually a pretty awesome thread :D. Nope, he never touched the diff... the 240D diff would have pushed his highway RPMs waaaay up.
The 5-speed won't fit due to the starter hump being on the driver's-side... AMG parts sound neat though.

maybe I should just fix the leaks... manual trans in turbo cars sucks. I actually bought one, a 300cd with a 4-speed. changed that right back to auto, there's a reason MB never installed a manual in a turbo charged diesel.

I love the car, but hate the mpg and highway rpm's. is there a better geared diff possible in the w116 sd?