Man...That don't sound like a very good experience
Can I instill some insights here? First, I got barrels of parts that fail on these with no warning what so ever. The clutch packs do not fail(unless ran low on ATF, or pre '93)These always have hard part failure(plantary gears, 2/4 hub and others. Unfortunatly its sounds like there are some people in your area that don't know electronics very well. The code #45 came from the ECM and all that code means is its stating there is a code in the TCM(Transmission control mudule). So there must of been codes stored in the TCM.
Throwing parts at it because some code reader gave a code is such a waste of money.
There are so many different ways a transmission can fail. Every trasnmssion has its own type of problem. Also, if you were in the area of 100,000 miles on your transmission, you better hope that $1700 got you new planet kit, 2/4 hub and rev hub. And, hopefully they aren't using "white box" parts.
If you have to guess, better make it an educated guess.
Have a good day