Guys...

I did this about 2 years ago...at a total cost of around $700!!! Call around salvage yards and locate a W140 4.2 119 (400SEL, 400SE, S420). It will most likely have ASR (mine had asr, which worked out well). I got mine for about 550. When you take the old one out, all you have to do is swap out the back plates, you will know what i mean when the time comes. I swapped the diff's out in under 2 hours myself, in my garage. Its not that hard.

Regarding the speedo calibration, dont touch the instrument cluster. You dont need to change any gears out. The speedo is electronic. There is no cable. It uses an electronic pickup on the tranny. Buy this:

http://www.abbott-tach.com/era.htm

Its about $125. It converts it electonically. Its easy to hook up (behind radio) and works perfect. And if you ever switch back, simply uninstall it. You can also run custom tire sizes and dial in the correct ratio to make the speedo accurate.

Let me know if you have any questions...

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93 300D 2.5 Turbo, Black/Palomino 273K
09 E350 Black/Black 41K

Regarding the ERA patch box, does that box work with a W126? I am getting ready to install a set of twin turbos in my 300SEL and will be changing out the 3.46 diff so I can keep tires on the car over a week.

My initial thought was to just get a diff from a 560SEL and do a direct replace since it has 2.47 and the twin turbos will more than take up the lag w/300 hp on deck. The 2.47 will also let me cruise at highway speeds at less than 3500-4000rpm which gives only 22mpg.

Does this make sense?

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McBear
Kentucky

1992 500E -- 1993 500E -- 1993 500E -- 1988 560SEC AMG
1992 300E -- 1988 300SEL TT -- 1980 280SL -- 1968 280SE

I need a Twelve Step Program...or a Twelve Car Garage!

Yes it will work. As long as it uses an electronic pickup, instead of mechanical cable, it will work.

I know my old 86 420SEL used a electronic pickup, so im sure your 300 does as well.

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93 300D 2.5 Turbo, Black/Palomino 273K
09 E350 Black/Black 41K

The lower geared diff should actually make your tranmission last longer... the engine and transmission "see" less weight because the mechanical advantage increase, that too is why you get better accleration.

What gearing does my '91 300e have? I think the ratios is ok, just want limited slip...

_Kyle

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The Wolf: That's thirty minutes away. I'll be there in ten.

I like it.

:-) neil