I spent around $500 dollars or more redoing my driveline the first time like you guys are doing now.
I put a spicer #051 in it and balanced it with new parts.
BIG MISTAKE

It caused me all sorts of problems and Finally Failed within one year.
These Drivelines are really not meant for repair.

I finally sent it to Driveline service of Portland Oregon.
They Have great service and a warranty.
When dealing with a mercedes driveline go to the pros.

Do It Right Or Do It Twice!
This is not a Diyer project unless you have a Grand to Blow.

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1984 W123 300CDT