Welcome to the forum,

I rebuild these transmissions, and a word to the wise...

Replace it always with a fresh one, and replace the torque converter bolts too....

These are always dealer items, but here in the USA(I presume you are in the States, and today is a BAD BAD day to look for parts because it is the largest Holiday here) I buy parts from these guys...

https://www.wittrans.com/dx/cgi-bin/dxserver.cgi?SESSION=CD3C44E65C43A8AA770E9C234B3B50F64D800EA17A2DBF91E4575AD233DEC94D6AC4BF2B2C9C972 07CDC366A6203910A&OPTION=OPTIONS

Here is the Mercedes look-up/prices

Mercedes-Benz Parts and Accessories Online from Mercedes-Benz of South Atlanta

Hope it helps,

Martin