Pinion Seal replacement

[estrellajon]

My differentials seem to leak grease from the pinion seal area. How hard is it to replace this part?

[jnenad16]

its easier(for me at least) to drop the entire diff, then take it aparts, replace all the seals(since the diff is out and apart). fill the diff up with redline 75w-90 synthetic gear oil. however, if you are attempting to do this yourself, it might take you entire day or maybe even the next day if its your first diff rebuild.

nenad

[estrellajon]

Yeah it is first time dropping the diff but I have all tools needed. I've dropped a motor off of a 911 just a matter of sequence and lessons learn from Porsche forums such as this site. What does it take to take to drop the whole diff off from a C280? Do I need to drop the whole diff if I'm just replacing the pinion seal or do you think its a good idea to replace all seals.

[jnenad16]

if your mileage is over 70k, I would recommend you replace all the seals cuz they are about to start leaking as well. the diff is not so difficult to drop, but it takes time. first you drain the fluid, then you will have to disconnect the driveshaft, then the axles. to remove the axles, you will have to remove the rear diff cover, and then remove the C clips that secure the axles inside the diff, slide the axles out of the diff. put the cover back on with only a few bolts just to hold it on. now unscrew the speed sensor, then support the diff with the jack if the car is being lifted of the ground or with a transmission jack if its on the car lift. once you have it supported properly and securely, its time to disconnect the diff mounts located in the rear of it. the diff mounts connect to the subframe, they look like rubber donuts. once you have disconnected them, take one good final look that everything is disconnected, once you confirm that, go ahead and lower the jack( and hopefully the diff along with it). now, to get the pinion shaft out, you will have to dissasemble the diff completely. to do this, first remove the read cover again, and there should be a nut securing the pinion shaft. use the impact air gun to remove it because its on there pretty tight. now, the pinion seal should be visible. it is also a good time to replace the bearing behind the seal as well(like I said, complete diff overhaul), when you dissassemble the diff, examine the pinion shaft, the bearing, and the spider gear for any scoring, blueing or galling. if you detect any of these, that means that you have some drivetrain problems. these could range from insufficient gear fluid in the diff to driveshaft missalignment. anyways, this is the way to rebuild the diff. I know it seems scary, but once you do it, it will seem easy.

nenad