National 710480 Differential Pinion Seal

I saw the other review posted with a one star for this product. All I can say is that National Oil seals have always been one of the best seals I have used. This one is no exception to my past experience. The only tricky thing about replacing the pinion seal is to get the pinion preload back as close as possible to original. I kept track of how many turns it took to remove the pinion nut and used this number to get it back to original position after the seal was installed. Over-tightening or under-tightening are both very bad for your ring and pinion gears. Be sure to clean the yoke where the seal rides on it and use a new pinion nut. The absolute best way to measure pinion preload is to remove the axles and ring gear. Then measure the torque needed to turn the pinion with an inch pound, beam style torque wrench. Don't over tighten the pinion nut because it has a crush sleeve inside. Tighten the nut in small increments and check with torque wrench to avoid this. I think a used pinion and bearings should be around 8 inch pounds. The important measurement is not how much torque it takes to get the pinion moving but how much it takes to keep it moving. There are charts on line to give exact specs for this. Anyway, this method is very time consuming but is the very best way to get it right. I have done many using the first method above and have had good luck however. Sadly no company can guard against someone ordering the wrong part number. It clearly says it's for an 8.25, not a dana 30.

Well made. Half the price compared to a local parts store. Fast shipping. Perfect fit and it fixed the leak. If it didn’t fix your leak, either you did something wrong or something else is wrong with your vehicle.

Fast shipping and the seal has held up great. Installed 4 months ago and it is good to go.

I messed up installing the 1st one but the 2nd 1 worked very well no leaks

In response to K Anderson's review. I found this review very informative. Unlike most reviews that just say the part fit and quick shipping Mr. Anderson steps up and explains the actual installation of the item. This was very beneficial to me as I needed to change the rear pinion seal on my 99 XJ. His seal replacement procedure worked out great. Mine is in and all is well. It would be nice if more reviewers took the time Mr. Anderson did to share their experience with the rest of us fledgling mechanics.

I always loved National parts but my XJ Classic Cherokee still has a leak after replacement. My Jeep has Chrysler 8.25" rear axle and there is no problem with the Yoke, axle or driveshaft. I wanted this part to work but it didn't, not this one. Work is done, my money is spent and I still have a leaky rear axle. Not recommended!

Very good quality. Arrived quickly.