Confirming Leak along front driveshaft assembly

[pili]

Front diff has been loosing about 0.5q per month and would just like to confirm my suspicions of the source. I've attached photo of passenger side, drive shaft assembly where drive shaft meets the diff. I'm guessing, per FSM, this is an issue with the oil seal being reused or installed incorrectly? I have records of a local shop replacing front diffs with aftermarket about 2 years ago (before I bought the truck). I've been topping off the diff regularly since finding the leak, but obviously need to order parts and fix the issue.

FYI, serviced with the wheels bearings with @2001LC in the spring so I'm confident in snap ring fitment and I believe the leak has been present since I purchased the vehicle.

Thanks for any advice! - Alex

 

[nissanh]

Install OEM oil seals.

 

[2001LC]

Yeah if adding gear lube and wet at that spot, that is a side diff oil seal leak for sure.

I like replacing that oil seal whenever a new front drive shafts (FDS) OEM, rebuilt or aftermarket is installed. It's a 50/50 chance they'll leak if not. Even then they need watching, especially if not and OEM FDS.

I keep a few of those seals and the inner snap ring on hand. This is not the same as outer hub flange snap ring (which will likely need replacing again, at it's least best to) that's installed with wheel bearing service.

Come on by and will replace it. Takes about 3, from time we roll in to roll out. You can leave it with me or just hang around or help if you like.

Meantime, keep topping off the diff. You do not want the diff getting to low.

 

[pili]

Yeah if adding gear lube and wet at that spot, that is a side diff oil seal leak for sure.

I like replacing that oil seal whenever a new front drive shafts (FDS) OEM, rebuilt or aftermarket is installed. It's a 50/50 chance they'll leak if not. Even then they need watching, especially if not and OEM FDS.

I keep a few of those seals and the inner snap ring on hand. This is not the same as outer hub flange snap ring (which will likely need replacing again, at it's least best to) that's installed with wheel bearing service.

Come on by and will replace it. Takes about 3, from time we roll in to roll out. You can leave it with me or just hang around or help if you like.

Meantime, keep topping off the diff. You do not want the diff getting to low.

Thanks Paul! I'll text you.

 

[bentonrover]

Also check your diff breather. Could be gummed up too. That will definitely cause them to leak from pressure build up.

 

[pili]

Also check your diff breather. Could be gummed up too. That will definitely cause them to leak from pressure build up.

Thanks for the tip, did check this first and it moves freely.

 

[2001LC]

Good thinking @bentonrover

 

[lordflexus]

I had the same leak on my LX. If your wheel bearing service is up to date, you can just disconnect the upper ball joint and bracket that connects to the tie rod, and pull out the cv to access the seal.

 

[pili]

Just following up on this thread. @2001LC and I pulled the driveshaft assembly yesterday and found that the inboard side was missing dust cover #41336-35020 which helps crud stay out of the oil seals. Turns out drivers side is missing too, but planning to redo with OEM driveshafts next spring, so hoping it holds for now. Unfortunately, the tolerances on the aftermarket driveshafts aren't as good as OEM, so dust cover isn't sitting as flush against the oil seal as from factory.

Long story short, seals looked to be reused, lack of dust cover, and aftermarket driveshafts probably all contributed to leak.