it sounds to me as if there might be "A" synchro problem, but I don't think it's across the board. It sounds more like the clutch isn't disengaging totally.

I'd find an M46 for a replacement trans if you're going to put anything in there. The M47s are harder to find.

At one point Volvo apparently deposited them in Turbo cars, but they weren't that common. The M46 hung out in most of the US product line with turbo engines. The biggest reason, I'm sure, is that the M47 isn't as strong of a transmission. Although the later M46 is reputed to be not quite as strong as the earlier ones. That I have little experience with.

The M46 is much less expensive used than is the M47. M47s are in somewhat high demand and pull $500 pretty easily on the parts market, if they are of respectable mileage and wear. The M46 models are all over the place.

--
1992 940 wagon, low miles
as well as others.