Welcome to the forum Shawn!

You can do it. It just takes patience, and accountability...

The magic tools: torque wrenches, 12point 30mm deep socket, 3" PVC plumbing coupling, some good o-ring picks(the Harbor Freight set will do), Transmission assembly grease, depth vernier, feeler gauges, one medium size electrical pliers(to remove the snap ring on the governor),and I made a B1 piston removal tool from a double-duplex metal punch-out metal plate with a ten-inch bolt.

Here is a meaty thread, yet in the end something went wrong:

Help - stuck on road 722.3 no 3rd/4th gear

Though this is for a 722.5, it is very similar:

Post 2 gives you an idea of the tear-down, and post 6 is the issue with reverse, and the use of the plumbing coupling to get to the reverse lip seal.

Post 12 & 13, are parts I would replace that are not included in your kit.

722,5 tear down which side to start from

I have all the service literature(factory 722.3 and ATSG manuals) on this transmission if you cannot get it from the link below. PM me we can exchange emails, and I can send it to you.The manuals are too large to post here.

Transmision work shop manual - Mercedes-Benz Forum

Replace K1 and K2(same part)

DIY Mercedes 722.3 722.4 722.5 Transmission K1 Piston Spring Repair Kit Install - Mercedes-Benz Forum

K2 spring number for tranny 722.3 - Mercedes-Benz Forum

The links from this post and the attachment should help:

300TE 722.358 tranny 3rd,4th are gone

It is 12 midnight, and going blank, but maybe others have some meaty-links..

Let me know what else you may need. While the tranny is out. replace your rear engine seal, and Mercedes updated the rear seal bracket. The bolts were changed too. You will need new torque converter bolts, and pressure plate bolts too..

Sign-up for EPC to get the latest correct part numbers..Only works with Windows on Internet Explorer with JAVA updated..

EPC-net Online

Best of luck,

Martin