Originally Posted by
fq06
Sounds like the diff is slipping under high loads. Can't think of anything on that truck that might make a sound like that other than a ball diff that's slipping.
Are the spring coils kissing? I think in a previous post you said they were but didnt go back to look, sorry.
Maybe a new spring, especially if you have the older spring and not the vts spring. Even if you have the more HD vts spring, they fatigue over time.
Do you have at least 6 pins? Sorry, again didn't scroll back a page or two.
+1 on what FQ06 said. I assume your talking about the RCShox center diff which is a big ball diff. The spring needs to be almost completely compressed. It is basically an over sized ball diff and they "Bark" when too loose. Barking is the sound ball diffs make when they slip and is very bad. The sound you are hearing may be your diff slipping.
Here is my RCShox center diff, note how compressed the spring is. Please ignore the stripped spur the topshaft bearings blew out and caused a bunch of slop that ended with a stripped spur.
Another view of the center diff and spring.