Transfer case, rear diff, and driveshaft slip yoke maintenance

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Cody Templeton

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I'm sure a lot of you have tackled these items already on your vehicles, but just wanted to add a bit of information from my experience.

Originally I was going to just suck the fluid out of the diff, but decided it would be best to just pull the cover to check it out. Glad I did, because it was pretty nasty inside. It took quite a few cans of brake cleaner to get all the burnt up gunk out of the diff that was stuck to everything. For those who haven't pulled the cover and done a good cleaning, it's probably worth it. While I had it apart I also painted the cover red and replaced the hardware to clean things up a bit underneath, but eventually will probably go to a B&M cover, and potentially change the gearing since I'm running 37's. I more wanted to get a service done on it since it had been at least 30,000 miles. E-locker doesn't take the LSD additive which is nice. Ended up just refilling with full synthetic 75W-140. Those Valvoline fluid bags are so much nicer than the regular plastic bottles.

Transfer case service wasn't anything interesting, they usually stay pretty clean since they just use ATF. Simple drain and fill with some Amalie universal synthetic ATF, but of course many will chose to use only Mercon LV.

The driveshaft service was the main thing I was wanting to tackle. For a while my truck has had the usual slip/bump noise from the rear, and I always assumed it was probably from the driveshaft slip yoke. After pulling the driveshaft I found that yes, it was very dry inside the slip yoke. Brake cleaned the splines on the transfer case and driveshaft and cleaned them off with a bristle brush as well. I greased the crap out of the splines with CRC engine assembly lube as it's got a bunch of moly and graphite in it. Got the driveshaft back in and drove it around and the slip/bump was completely gone.

I need to get the front diff done yet as well as getting all the lights leveled, but figured I'd just post a quick update on things.
 

Gumby

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Originally I was going to just suck the fluid out of the diff, but decided it would be best to just pull the cover to check it out.
I agree this is a good call.^^^^^^ Especially since most of us are not the original owner. It is good to get a look what is going on in there. Remember what I found? Nice write-up.
 

Jhollowell

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I'll be curious to see how long the slip yoke clunk stays away. i've greased mine a few times with different grease and it always comes back within a few days. Few months ago i replaced the entire yoke and U Joints hoping that would solve it and it partially did. When it rains or its wet outside it clunks and when its dry, its gone. I don't know why its like that but i guess its better than a constant clunk. I've wondered if changing the seal would help at all.
 
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