I am considering replacing the rear diff with a lower ratio as I primarily drive this on the highway. I have a friend at the Local salvage yard that likes me and is giving me some parts I need for FREE (like the speedo i replaced this last weekend)! He has a few rear diff units out of an 1982 and 1983 240D but does not know the ratios. I don't know my ratio either? Can some one help me on the ratios for both of these units.
I am to lazy to check it the old fashion way.
Regards,
Bryan

The ratio is stamped on the case on a machined
flat toward the bottom, rear of diff.
A scrapping with razor/knife works well.

My Ratio is 3:69 as are both the rear diff's my friend has. I wolud like to find a 2:75 to 3:00 Ratio but what vehicle would I find this ratio that would swap into my 114?
Regards,
Bryan

Not sure if this is relevant or not, but try a search on diff ratios. Seems just a short while back a similar question was asked, and there was something regarding the rear diff's from a 280SE being good for a swap due to higher (lower number) gearing.

Might be worth a try.

Originally posted by MikeTangas
Not sure if this is relevant or not, but try a search on diff ratios. Seems just a short while back a similar question was asked, and there was something regarding the rear diff's from a 280SE being good for a swap due to higher (lower number) gearing.

Might be worth a try.

I think that thread was the one regarding the
280se 4.5 -108 chassis diff. [ which you have]
That is a common swap on the swing axle , enclosed
axle tube style. Nice ratio of 3:27 for converting
those high reving in line 6's.
These will not fit the 114 chassis as 114's were
the first of the new generation suspension and open axle
design. All 114's were IL6 and you have the best
ratio of that vintage. [3:69] The other was 3:92
However, you may want to check into the 116 chassis .
300SD had a 3:07 and the 450SE's had a choice of 3:06 or 2:65 [there's a cruiser for ya' ]
Some of the 123 Turbo's might be what you are looking for also.
I have never done any open axle swaps, but I think some of these are interchangeable. Worth a look-see.

Can someone 100% confirm that a 116 rear diff unit will interchange in my 114?, I have found the 3.06 and the 2.65 ratio out of a 450SE and will buy it to do the swap if it does interchange!
Thanks!
Bryan