51 Mercury Leaking differential

The differential in my 51 Mercury is leaking through the seal where the driveshaft attaches. Do I have to remove the differential to replace this seal or can I do it with it still on the car. Thanks

 

Remove drive shaft, remove pinion yoke, remove old seal, clean everything up, install new pinion seal and put all back together. pizzacake.

 

You can do it without pulling the center section, just remove the pinion nut and yoke, replace the seal, and reinstall the yoke/nut. DO NOT overtighten the nut, and put some locktite on the threads.

The OEM seals in these were leather, and if the replacement is leather pre-soak it in some motor oil until it's soft before installing it.

 

Thanks. Sounds like something this old 3/4 of a century old guy can do.

 

Before you remove the pinion nut, mark both the nut and the housing so you can reinstall the nut in the exact same position.

 

Good advice from Mike51Merc. I was going to suggest the same thing. If you don't mark the position of the nut when you put it back on, the lash between the ring gear and pinion gear will change. That will make your rearend noisy and you don't want that.