Rear pinion seal leak SU7 rear end

[MadMatt3883]

I have a 19 Silverado with a little over 45,000 miles.  I recently discovered a rear pinion seal leak. I cannot find detailed instructions to do the repair (torque specs, one time use/reusable bolt etc.). Pinion seal replacement seem to be the same for most axles, I just want detailed stuff like torque specs. Anybody have snippets from a service manual that can help? 

[swathdiver]

Before you take the pinion off, you need to measure the rotational torque in inch-pounds of the axle.  Preferably without the brakes on.

 

When you torque the new nut back on, add 3-5 inch pounds more to that original number to keep pressure on the crush washer.

 

Go slow for if you add too much torque the axle will grenade itself in short order.

[MadMatt3883]

I was given this. So based on what I’ve seen I’ll have to take the wheels and brakes off to do this. I have a digital torque adapter with a “peak torque” setting which will freeze the max torque applied after completing. You think that will will be sufficient to measure the torque? Also does it matter which direction I turn the the pinion nut to measure that torque?

 

Edit: After re-reading this it looks like I just need to measure how much torque it takes to remove the pinion nut then add 3-5 lb in when putting the new nut back on. 

Edited February 4, 2025 by MadMatt3883

[IOMTT]

Mine pissed out a small amount of gear oil during the 0F weather. Upon inspection, the reason appears to be the vent hose run horizontally, small bellies allowing a few drops of water to accumulate & freeze. Another snowflake engineer fail.

You heard it here first.

[Grumpy Bear]

My 2015 had this leak. Found it to be leaking around the seal not through it. New seal with a smear of RTV clear on the O.D. then drove it in. Leak free since. 10 years now. Didn't know about the torque spec. I used a witness mark. 

[MadMatt3883]

Torque spec is different on the previous gen I believe. 

[swathdiver]

There's no torque spec to crank down on the pinion nut.  Torque is established by the rotational torque reading in inch/pounds.  

 

You don't measure how much torque it took to remove the nut and add 3-5 pounds when putting it back on.

 

Some guys like Marty who use witness marks get away with it.  I reckon that Marty didn't crank past the full width of the witness mark when he put his back on.  Half a hair maybe, Grumpy Bear?

[Grumpy Bear]

2 hours ago, swathdiver said:

There's no torque spec to crank down on the pinion nut.  Torque is established by the rotational torque reading in inch/pounds.  

 

You don't measure how much torque it took to remove the nut and add 3-5 pounds when putting it back on.

 

Some guys like Marty who use witness marks get away with it.  I reckon that Marty didn't crank past the full width of the witness mark when he put his back on.  Half a hair maybe, Grumpy Bear?

 

You nailed sir. Rotating torque would be more accurate and less risky. But I sometimes I am that guy who gets aways with something just because I don't know that I can't.