This is a very, very common problem on 940s.
The capacitors inside the speedometer leak acidic fluid onto the PCB which eats it away.
This corrosion causes damage to the PCB tracks, fortunately it is repairable. As are dry solder joints.
What unfortunately also happens is the IC chips go bad. They are no longer available. I may have a few spares if you’re seriously interested in a repair of your cluster.
It doesn’t make sense that both your cluster and the rear axle speed sensor were both faulty at the same time. The cluster fails 10 out of 10 times whereas maybe 1 in 10 cases the wiring to the sensor becomes damaged or disconnected.
