Swapping a auto to a manual - PeachParts Mercedes-Benz Forum

trigun7469 · #1 06-23-2006, 10:52 AM

I am considering buying/trading for a 92 300D. I would like to convert it to a Manual, Below I robbed another post that went into great detail, but was wondering what parts are needed for the 92 since its newer? will the older trannies bolt up? is below any help or is the 92 a new ball of wax?

Quote:

5-speeds are hard to find (unless you order one from over-seas - Yes that 300D on eBay would have been a candidate). I used a 4-speed manual from a 240D and find my new gearbox to be very comfortable at all speeds, though I did upgrade to 16" wheels to compensate for the lower gearing.
You may find buying an entire 240D the best route (that's what I did), since you will need many of the parts. Find one with a good clutch, clutch master cylinder, and transmission.
Here's what you will need to do:
Obviously, remove auto. transmission, entire drive shaft and center baring, shifter, and brake pedal assembly from the 300d. This will entail removing the exhaust, and dropping the engine a bit to expose the nearly impossible to reach top tranny/engine bolts.
Also, remove the stock 300D flywheel - hopefully in your case none of star headed bolts strip. Three did for me, thus I spent quite a bit of time drilling the heads off!
You will need to take the complete 240D drive shaft and bearing assembly to a good dirve shaft shop to have shortened and balanced. Since the 5 cylinder engine is longer and the manual transmission is shorter than the AT, neither stock front drive shaft will fit... Note that it will be your responsibility to determine the lenght the 240D front shaft will need to be cut back to - be certain to check your math, else you may end up with an expensive lawn ornament! The bearing and rear half are interchangeable, so you can pick the best parts there. This cost me about $300.
The manual tranmission shift rods will need to be shortened the same amount as the 240D front drive shaft... get out your hacksaw.
Swap the brake pedal assembly w/ that from the 240d manual - again, acquire one with a good clutch master cylinder.
The 300D crank shaft is drilled for a pilot bearing. I'm not certain if it is a readily available size, however. I had a shop grind and slightly larger one down to fit...
Install a 240D or manual tranmission 300D flywheel. Make certain the clutch surface is smooth.
I would suggest replacing the slave cylinder on the manual transmission before installing it. It may save time and hassle later. Also, replace the flexdiscs on the dif. and transmission.
The rest is straight forward. Oh, you will need to modify the wiring for the reverse lights and starter cut-off. You will be able to remove the accelerator linkage on the head with some slight modifications, which results in less clutter and great improvement in pedal response.
I would strongly suggest going through with such a project. Acceleration is improved quite a bit. The result is a much more fun diesel

mybenz123 · #2 06-23-2006, 07:54 PM

trigun.

The 92 300D is the w124 chassis and the 300D that
they are talking about is a w123 chassis.
As far as I know these transmissions are not interchangable.
I'm not a 100% sure about that but someone here
will know for sure.

Louis.