The strut mount on my 92 4wd legacy sedan is broken. The rear suspension was just swapped from a 4wd wagon. I still have the old 2wd struts. They bolt to the knuckle above the hub on the 2wd and in front of the hub to allow axle room on the 4wd. Other than the stronger cartridge on the wagon are these struts interchangeable?

4WD & 2WD rear struts are not interchangable.

I can get some 4wd wagon struts from a friend. The FSM says they are the same length but stiffer. Will they fit?

Firstly, the FWD struts are inline with the axle. The AWD ones are offset back and raised slightly. Therefore height will be different. The AWD strut body is smaller.

 

However irregardless of height, the way the metal at the bottom of the strut is bent will not fit on the rear FWD spindle. I tried it when I did my AWD swap. I was just going to use the rear AWD struts on the rear FWD spindles on the donor car, so it rolled. I ran into the issues I mentioned, so I had to swap the rear AWD springs on the rear FWD struts, so they would bolt up to the rear FWD spindles.