Rear differential plugs and RTV gasket maker

[westslope]

I am draining and refilling the rear differential fluid. The FSM calls for new new plugs for the drain and refill hole.

Is there an issue with cleaning up the old ones with brake cleaner and then using Permatex RTV Gasket Maker? Might be able to save a few pennies. Make that 60 beaver bucks for the pair of plugs. (!)

Should I allow the drain plug to sit a while before adding the 75W-140 gear oil/diff lube?

 

[IM1RU]

I have never heard of anyone replacing the drain or fill plugs on the rear diff, unless they were trashed (I don't know how you'd trash the fill plug), and you shouldn't need RTV on them either. YMMV.

 

[westslope]

The FSM calls for replacement.

A few people here and there on the web coat the threads of the plugs with RTV before re-installation. Ultimately I went this route. As per Permatex's instructions, I hand tightened the plugs, let them sit an hour and then torqued them to 32 ft-lb. By the time I drive the X, it will be more than 24 hours later.

@IM1RU: Frankly, I would not be surprised if RTV or similar is not necessary.

 

[IM1RU]

Fair.... I will add that the FSM says to replace lots of things that no one ever does... especially mechanics that don't work for dealerships.

Your rig, your way, 100% That I respect.

I'm a little surprised that no one else chimed in on this.

 

[TerryD]

The FSM calls for replacement.

A few people here and there on the web coat the threads of the plugs with RTV before re-installation. Ultimately I went this route. As per Permatex's instructions, I hand tightened the plugs, let them sit an hour and then torqued them to 32 ft-lb. By the time I drive the X, it will be more than 24 hours later.

@IM1RU: Frankly, I would not be surprised if RTV or similar is not necessary.

Which differential do you have?

 

[westslope]

Which differential do you have?

It is a 2006 OR. That one. ;-)

BTW, drove the vehicle for about 3 hours since the drain and refill. Does not appear to leak a drop.

 

[westslope]

@IM1RU: I usually replace the crush washer on the oil pan drain about once every 3 or 4 years and have never had an issue with oil leaking through that drain plug so yeah, I am well familiar with the concept of ignoring FSM recommendations.

Sometimes it hard to know when to carefully follow the FSM recommendations to replace items and when a more relaxed approach can be taken.

 

[TerryD]

It is a 2006 OR. That one. ;-)

BTW, drove the vehicle for about 3 hours since the drain and refill. Does not appear to leak a drop.

The M226 should have two pipe thread plugs that do not require any sealant to seal properly or have crush washers.

 

[westslope]

The M226 should have two pipe thread plugs that do not require any sealant to seal properly or have crush washers.

Agreed. As I was re-using the old plugs, and the new ones come with thread coatings, so I wanted to make extra sure. That said, I have read a few accounts of others re-using the old plugs with no sealant.

Glad I did it. There was almost zero material on the magnets but the fluid was dark and opaque. Transfer case and front diff are next. Then a drain and refill of the AT. I really should replace the rear wheel bearings and seals too.

It never ends......

 

[TerryD]

Agreed. As I was re-using the old plugs, and the new ones come with thread coatings, so I wanted to make extra sure. That said, I have read a few accounts of others re-using the old plugs with no sealant.

Glad I did it. There was almost zero material on the magnets but the fluid was dark and opaque. Transfer case and front diff are next. Then a drain and refill of the AT. I really should replace the rear wheel bearings and seals too.

It never ends......

I wouldn't disturb the rear wheel bearings unless they are actually bad.

 

[westslope]

I wouldn't disturb the rear wheel bearings unless they are actually bad.

I had a bit of leakage through the PS rear axle seal that messed up the rear brakes a little. About 4 years ago, I did the rear axle breather modification, replaced brake parts and thoroughly cleaned up the area.

Thought about switching out the rear wheel bearings at the time but put it off because it requires getting a shop to press them back on.

Am now thinking about this again as I hear a subtle whine that seems to be coming from the rear of the X. It occurs when the foot is on the gasoline pedal and the motor is working at near or above 2,000 RPMs. In other words, while coasting there is no subtle whine.

Could be the uni-joint? I recently squirted a bunch of grease into the rear uni-joint. It was replaced with a grease nipple-equipped aftermarket unit in late 2014. That eliminated the vibration at highway speeds I had been experiencing at circa 163,xxx km (101,xxx miles). The X currently has 239,xxx km (149,xxx miles) on it.

For perspective, when I turn on the radio loud or play music, I do not notice the whine.

So, for the lack of better, more precise diagnosis, I'm taking a long-shot guess that the whine is coming from one of the rear wheel bearings but then it frankly makes no sense that the whining quits when the engine is not under load. Suggestions?