if its so easy, then why did a pro builder fail to put it together correctly ?

I saw your post on forabodiesonly last week about this same issue. John replied to that post telling his side of the story, I will cut and paste that below. Sounds like John tried to make it right, but you refused to give him the chance. Also, how is it possible to put the sprag in "backwards"? The outer cam is riveted to the case, and the inner race can go either way. The springs and rollers really can only go in one way. Something sounds fishy about that.

John's reply on forabodiesonly......

When Darrel notified me that there was a problem with his 904 transmission I immediately got in touch with the technician that was working on the car for him to help troubleshoot it. The transmission had no forward gears and after some over the phone diagnosis it was apparent that the transmission would need to be removed from the car to be looked at. Understandably, Darrel wasn’t happy with that news. I apologized and assured him that I would make it right. I told him that I would pay for the shipping to have the transmission sent back to my shop, make whatever repairs were necessary, and then ship the transmission back to him within a couple days of when it arrived, all at absolutely no cost to him. During our phone conversation I made that offer to him at least 4 times, all while he was yelling at me, interrupting me every few words, and being totally unreasonable. I finally told him to cool off for 24 hours and call me back the next day so we could discuss it and I hung up the phone. I never heard back from him until he emailed me a link to this post. I totally understand that he is upset that his transmission has problems, I would be upset too if the situation was reversed. I tried to do what I could to resolve the situation, but he refused to even have a rational conversation with me about it.

I recommend talking to this gentlemen. Honest. Builds a great product.

https://www.andrewsracingtrans.com/

if its so easy, then why did a pro builder fail to put it together correctly ?

Sorry for your trouble BigDad.
This is a little off topic but, I’m a mechanic for 40 yrs, never rebuilt transmissions. I once broke pump gears in a 904 and swapped parts from a /6 904, worked great. In 2011 I bought my wife a new Mercedes, V6 AWD. Salesman asked if I wanted extended warranty, I said no I’m a mechanic.……. who needs a warranty. 2 years 2 months later it’s out of warranty. Trans starts going bad. Mercedes says $10k to replace. Can only put in a new trans, can’t repair it, or reprogram a used one, so can’t get one from a wreck. I was so pissed I let car sit 8 months. Borrowed a car from a family member for wife. One day I decided to tear it apart. Laid everything out nice on a tarp on garage floor. Found bad parts, but can’t buy the parts in US. Mercedes had lock on parts. I tracked parts down from a bearing number and was able to get everything i needed from a trans guy in France !!! I put it all back together and it was perfect. Kept it for years and eventually sold it to a friend of a friend. It’s still going strong today. I believe it was under $500 for parts imported from France and $250-300 for the Mercedes trans fluid they were nice enough to sell me where I bought the car.

I feel for ya. Back in June of 2019, I posted a thread about John's workmanship, with a picture or 2, on my 48RE tranny. He also replied to my post, eventually. Blamed his "employee" for the F##kup's, yes Plural, and then said he offered to make it right. He originally agreed to pay for the converter swap, because he sent incorrect one, twice. Then after I had bought the correct one myself and had it swapped, he offered to pay me a couple hundred bucks for the mess. Claimed I wasnt nice, so I wasnt nice after that. I try and call him every once in a while, just to see how he is doing, for old times sake. Jim.