Rear differential leaking ...

[x6369x]

Hey all,

Have any of you heard of this?

 

I took my truck in to my local GMC dealer for the 3K oil change back in December. I happened to be watching the mechanic, and he noticed that the rear differential was moist. Upon removing the drain plug, a bunch of diff fluid came oozing out. The mechanic allowed the excess fluid to drain out, and said that the factory probably overfilled it and possibly damaged the seal.  

 

Well, I took it in for the 6K oil change yesterday, and the same mechanic noticed that the rear diff had been leaking again and the fluid level was low. The mechanic topped off the fluid, and the service writer ordered a new seal.  It should be in within the next couple of days.

[CMNTMXR81]

It's not uncommon for 12 bolts to leak out the front seal (the input shaft off the driveshaft).  Overfilling it shouldn't do any damage as the fluid isn't under 40psi of pressure in there like the engine is.

[THE BIGPUNN]

i have never heard of a car or truck any make or model that eventually didnt have a problem with the rear end gasket. during normal driving look at the rear end of trucks that are in front of you at traffic lights and youll see what i mean. i think the main thing is too keep an eye on the gasket and be ready to replace the gasket whenever needed.  at my old job the owner just bought a brand new silverado 1500 to plow with and sure enough, with only 500 miles on it the gasket went.

[RyanbabZ71]

topped off the fluid

 

Your not supposed to top off the rear diff fluid.  It is supposed to be a certain distance below the fill hole.  It says thi on the rear diff itself on a blue tag.

[CMNTMXR81]

The old skool rule of thumb, err, finger is that when you stick you finger into the fill hole, if you can feel the fluid, you're fine.  So essentially anything below the fill hole is acceptable.

 

What most likely happened was that since yours was sooo overfilled, that there was nowhere for that excess fluid to go but out.  It just happened to seap out the front collar bearing.

 

Now that it has been brought to the appropriate level, watch it.  if it continues to leak, then you'll need to have the seal replaced, otherwise it should start to dry up if it was just excess overfill.

[jetskinjoe]

I have a leaky rear end too, on the truck that is. I've resealed mine several times and mine seems to be leaking from the bolt holes. Ive used pipe tape, thread locker, silicone and even rubber washers and it still leaks. What should I do other than weld the holes closed?

[The Factory Man]

<br />I have a leaky rear end too, on the truck that is. I've resealed mine several times and mine seems to be leaking from the bolt holes. Ive used pipe tape, thread locker, silicone and even rubber washers and it still leaks. What should I do other than weld the holes closed?<br />

<br /><br /><br />

My 2005 1/2 ton differential fluid level should be no more than 1/2 inch below the fill plug. If it is any higher than that it is overfilled. This is specified in my owners manual so check yours. Other differentials that are used require other fluid levels. Look at your manual and do not overfill if you don't want leaks.

[Zembonez]

Most trucks I have owned (and my jeeps) have eventually had seepage around the read cover or at the front seal but I have never experienced and real 'leakage" to the point of having to add fluid between changes. It's a pretty common thing with rear axle housings. If you have a leak that is actually resulting in drips on the garage floor, you have a problem. Otherwise, I'd not worry too much over it.