Had a mechanic replace the left and right side axle seals. The left side he can't get it to stop leaking. He put in one and it leaked. Then he put in a second one and said there is a slight leak but a lot better. After a 1 hour drive I let the car sit for 3 hours and there was literally a puddle about 3 feet long of gear oil He doesn't think it's the differential bearing.. He suspects it might be a bad ball joint causing the axle play.

What are some other symptoms of a bad differential bearing?

 

Dealer seals?

Those are a royal PITFA to replace. Is your guy using adequate seal drivers?

 

The first one was an OEM sealer from the dealer and the 2nd was aftermarket. Seal drivers? what are those

 

I believe a mechanic should be able to easily decipher where the play is. I don't see how play in the ball joint is going to make the seal leak like that. Does this mechanic have a lift? Verify there is no play at the diff bearing.

 

Thats exactly what I thought. Never heard of a ball joint causing an axle seal to go bad. Yes he has lifts.How do I get him to verify this?

 

Make sure he's getting the seal to sit properly. It needs to be forced in and tight. I used a long piece of grey PVC same diameter as the seal, then tapped a mallot on the end of the PVC to snap it in place properly. Worked like a charm and leak is completely gone.

If he's not getting it to seat properly, it will leak.

 

Also make sure where the seal is sitting that it's not damaged or scored heavily. If it's not smooth where the seal sits, it'll cause a leak then too, and no matter what kind of seal (oem, aftermarket) you get will even matter. Make sure he didn't damage that part first.

 

Similar experiences with leaking seals. Replaced right shaft on 2000 SE MT. Only boot was torn, factory seal was intact and dry. First try, aftermarket seal (Beck/arnley), result . . . leaking seal. Second try, . . . installed a Nissan seal. Was VERY careful to get good seat. (Wish I'd read thread before job. PVC pipe to drive seal is extremely good idea. Took me a couple hours to get seal in!). After all that, still leaking but much less. I've decided to live with a couple drips on the drive after work each day. Can't help but be suspicious of the axle (Advanced Auto $70 new GLS?????), as it has a vibration above 70 mph. Another suspect is the suspension play. At 115K and suspension is getting a bit "sloppy". Diff bearing is SOLID . . . not a suspect . . . original seal did not leak. Any thoughts would be greatly appreciated.

 

it's not your seals if he installed them properly.
It's your diff bearing inside your tranny has too much play causing shaft to move too much and leak in tranny end.
Need a used trans bro sorry. They're known for that especially 00-01