The Rear differential pinion seal is leaking and I want to replace it. Does one need to remove the differential to do this or can one leave it in place? Is this an easy job? It is a 98 Forestor.

You'll need to remove the nut that holds the shaft to the mounting plate. You could probably do it on the car.

i have never heard of this happening even on the 20+ year old older generation subaru's. from all the diffs i've played with i'd guess this could be done in the car as there isn't much "on top" of the diff that you'd need to get to and can't access.

 

as a last resort, the diff isn't that hard to remove and you can drop it on the ground with the rear axles still attached as well. a bit of effort getting it back in place by yourself (60 pound diff with axles still attached) but just a few minutes of grunt work and it's all good.

Thanks for the advice. I checked the differential oil level yesterday afternoon to make sure it still has oil and it still had plenty. It just looks like it is leaking a lot. Two years ago it was very low and I drained it and replaced the oil. So the leak is pretty slow. I might put in a new seal when the snow has finished melting and the ground is dry.