Front diff input pinion oil seal

[Mike W.]

I obviously know the basics. I'm a BMW guy and they have stupid complicated procedures for anytime you even think about loosening a pinion nut, relating to a crush ring and preload, measurement of all that etc.

But this is a Nissan. 03 QX4 to be exact. The input seal on my front diff is leaking, pretty good it looks like. Is it a simple unbolt things, R and R the seal, then torque things back up? Or measure preload etc. I see a reference to a special tool in the factory manual, but nothing about what it's used for. Or is it in the real world, all of that, but mark your spot, retorque to that exact spot or just a *** more, and you'll be good?

Again, this is on the front diff.

[VStar650CL]

The pinion nut torque spec is 137~217 lbs/ft (see PD-18 here):
https://www.nicoclub.com/service-manual ... 3%2FPD.pdf

Torque it to the minimum, then check the pinion turning torque with an inch-pound torque wrench (tires removed). Preload should be 2.6~13 lbs/in (see PD-19). If it's low, tighten the pinion nut in stages till the preload is normal. It probably won't need much, the crush and pinion height should already be on spec. You don't really need a special tool, but you will need socket adapters to put an inch-pound wrench onto the big pinion nut.

[Mike W.]

Thanks VStar, I had looked at the FSM, but as usual didn't really see a whole lot in it, maybe I just didn't look hard enough. I feared the correct answer would be about what you described, though hoping otherwise. I'll probably just go low tech, mark the position of the nut on the pinion shaft and return it to there. With red locktite just to be sure. Given that it's the front and it already has 180K on it, it's not going to see a whole lot of miles under load.

[VStar650CL]

The safest course would be to bring it back to the matchmark or the 137 lbs/ft minimum, whichever is higher. Other than that, sounds like a plan.