I need some help in my research for replacing the rear main seal in my 2004 ML350.

What special tools might I need? I have ordered a proper crankshaft seal installation kit. How long of extensions are needed?

Anyone have a breakdown on the removal procedures in order of removal, such as: ex. will I need to remove exhaust?

some items I thought of were: transmission cross member, drop the transfer case, then use a reverse torx or suitable metric socket with extensions to remove the bell housing bolts.....

Any other parts to replace while I am in there and if so are there any specific tools involved?

ex. front transmission seal?...need special tool?

No exhaust removal needed. These guys documented it for you 8 years ago:
I need a PDF DYI rear main seal replacement. - Mercedes-Benz Forum

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Prost!

Thanks for the link. The pics embedded along with the AllData pdf files is great.

I do need to know if any of the bolts need to be or are suggested to be replaced?

No, but if you live in salt spray country, I would probably replace the driveshaft bolts while there. This reminds me that the front driveshaft bolts are tight access - I needed a short socket and various extensions to remove mine.

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Great info. I heard that the flywheel bolts are one-time use stretch bolts. Did you replace yours?

It's good practice, although the procedure doesn't specifically call it out. Going 40NM +90 degrees may mean it exceeded its yield strength.

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All is better after replacing the rear main seal. It was a pretty involved job with pulling the transmission and all. Definitely not a job I want to do again any time soon.

The proper rear crankshaft seal tool was wonderful. It was purchased from s-g motorsports. I went with Mercedes seals and retaining plate and also used their sealant on the retaining plate for good measure