For anyone reading this thread:
Well everyone gave advice on the most frequent issues. I mean DIY sometimes is a real PITA. I am working on the Transmission from my Van and managed to bend the input shaft and do some other damage. When I worked as a Diesel Mechanic I worked in Fuel Injection and on the Engines and nothing else so the innards of a Transmission are new to me.
Learing by experience can be a PITA>

Here is what is in the ASTG Transmission rebuild manual on troublshooting the no forward motion, see pic. Note the ASTG Manual is extremely minimal and there could be stuff not mentioned that can cause the issue.

There is also stuff like the B2 band could be worn out and or the Dog Bone pushrod needs to be longer.
It is a wonder that sun valley (got my used rear trailing arms from sun valley like 9 years ago) did not tell you to check the Dog Bone pushrod length.

The 2nd pic is using a vernier cliper to check the Dog Bone pushrod for the proper length. The digram is kind of poor but I believe the Valve Body needs to be removed to do that but I am not sure.

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84 300D, 82 Volvo 244Gl Diesel