I don`t know how close the measurements are between the SEC and the SD. here is a thread JOHNHEF did with pictures.

http://www.peachparts.com/shopforum/mercedes-benz-performance-paddock/242313-116-126-differential-swap-pics.html

I was thinking if you don`t want to change the yoke to use the smaller flex disc, maybe use the rear driveline off a gasser. I think the rear section is the same length, then have it balanced with your front section.
you would then have the Diesel flex on the front and the gasser flex disc on the rear.

Just a thought.

Charlie

That's a great idea!

Less work = more fun!

What about the axle seals????

Might as well do it. The sides are easy. You just carefully pry them out and use a large block of wood to pound the new ones in "straight and level".

The pinion seal... Well... You already know what is involved to get to that one and do it properly.

Sorry....

Are the seals and sealing surfaces on the axles the same size between the two cars????

Look up the part# for the car the Diff came out of. there are different sizes of seals.

Charlie

Found a 160 MPH speedo out of a 107. The differential was gone.

I can't find a paper tag on the cluster. Any way to figure out what it may be calibrated for????

So, the OD of the seals are the same, but it is the ID that is different????

Outer diameter of the seals are definitely different between some differentials. Inner Diameter should be the same as far as I've seen.





.

Hmmmmm......Someone should make a list of the correct seals then, because Nobody will know the answer to this question....Robert

Grease the springs
 

I just replaced the seals in a Differential, I knocked the first on in, flipped the diff over and knocked the 2nd one in. Then noticed the spring on the inner lip of the seal came off and was laying in the diff. Both sides.

First time I have had this happen. the old seals didn`t have springs.

Be sure to grease the Springs, pack some grease around the spring to help hold it in the lip.

Hope I can work them back in, buying another set of seals doesn`t excite me.

Charlie

Yes,

The garter spring can be a real challenge to replace!

Now, if only to know what calibration my 107 speedo (160 mph) has.....?????