Just Say No To RTV.

By Shawn Pagan

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Simple Maintenance: One of the simplest things that is often overlooked on our trail rigs is differential maintenance.  When was the last time you swapped your diff fluid and inspected your ring and pinion?  For many of you the answer may be "never."  If "never" was your answer, consider that this can lead to drastic problems if left unchecked - especially if you often wheel in wet or muddy areas or if you spend a lot of time in rockier areas where the diffs are working hard and absorbing the blunt of the blows, either from the rocks (thru the tires and axles) or the drivetrain itself (via your heavy right foot).

Perhaps you're the type that drives yours on a more frequent, perhaps daily, basis and maybe you even have your oil changed at one of those "quick lube" places where they change your diff fluid by sucking the old fluid out, flushing the diffs (if you're lucky) and then refilling them with clean fluid.  

Regardless of the type of wheeler or driver that you or your rig are, I would suggest pulling the cover every so often (I pull mine about every 6000 miles - or about every 4 months, whichever comes first)  if for no other reason than to check the ring and pinion and the torque settings on the bearings. 

Checking your diff is a simple job and it can be done in your driveway with a few normal tools in about 30 minutes.

Now, thanks to our friends at LubeLocker, the entire job just got simpler and a lot cleaner.  These guys have used something very similar to head gasket technology and placed it on a gasket for your differentials. They have taken a thin sheet of steel and placed it between two layers of elastomer. This "sandwich" creates a gasket that when properly torqued down creates a seal between the diff cover and the mating surface on the pumpkin without the use of any sealers or RTV.

Cross Section of the LubeLocker (From the LubeLocker website)

Why does this make the job of changing your diffs easier then ever?  Follow along as I install a LubeLocker gasket on the Dana 44 in the back of my Jeep.

The Dirty Deed: As you can see, my differential gets a fair amount of abuse on the trails, which is one reason I like to inspect it fairly often.  On my rig, the diff sits far enough below the gas tank that I can access all the bolts without any issues, but, if it didn't I would need to jack up the body slightly and let the suspension droop a little to get easy access to the bolts.

Dana 44 diff in a 1998 TJ

Two bolts left in place

After I loosened all the bolts on the diff cover, I removed all but two up towards the top of the cover.  Then I used a soft hammer to tap on the diff cover to loosed it up on the RTV that was applied during the last install.  If the soft hammer doesn't work, I resort to using a screwdriver and tapping it between the cover and the housing. 

Once the screwdriver is inserted, I can twist it a little and this usually separates the seal the RTV has on the cover.  You may have to insert the screwdriver in more then one place to completely break the seal. By leaving the two screws in the cover it allows me to drain the diff in a controlled manner into my catch pan without the whole cover coming off and the fluid spewing everywhere.

Using a persuader to remove cover

Screw driver inserted to drain diff

RTV protruding thru the bolt holes

Close-up of RTV

Once I have drained the fluid I removed the last two cover bolts and inspected what I had.  To me, everything looked good inside the diff so I could now put it back together... but first I had to clean up all this excess RTV.  If you look closely, you can see the residue left by the RTV sealant on both the cover and the diff mating surface.

Diff mating surface.  The discoloration is RTV that must be cleaned up before reinstallation

You need to clean the build up off the mating surface and out of the bolt holes

RTV on the cover. All of this will need to be cleaned

Yuck! RTV residue being peeled off of the cover

Cleaning the RTV usually just requires a little patience. However, it can be longest part of servicing your diff.  I generally use a razor blade to scrape the RTV off of the surface of the cover and a small scraper to clean up the mating surface on the housing.  I also run my hand carefully over both surfaces to look for small dings or scratches or places that I may need to file down or clean up before I put the cover back on.

Cleaned mating surface

Bolts that will need to be cleaned

Inside of cleaned cover

Cleaned up bolts

Once I had everything cleaned up (including the bolts, because I don't want to force RTV back into all of those holes), it was time to lay another bead of RTV on the cover and - oh, wait, this is where LubeLocker's new differential gasket comes in.  Their new gasket does not require any RTV or any other material outside the gasket. Great!

LubeLocker, and instruction sheet


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