I had an Allison I built do similar, single sided c1's were installed incorrectly, no forward gears but had reverse though...
You would have had 5th if you could of ever got there. But what your saying is exactly why this is so strange. The only clutch that would give him no 1st or reverse would be C5. So unless there is some C5 clutch discs laying on the original builders bench or he forgot to reinstall the C5 apply piston seals I don't see how he could lose C5.
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