After a complete cleaning, it was discovered that there are 2 magnets in the transmission that are there to capture shavings!! New filter and epoxy patch, going to go without diff lock and see how she runs!
I have had the same problem, the problem with mine is the the (?) that locks the wheels together inside the transmission burst a whole in the bottom of the transmisson. I fixed the hole (aluminum weld) and put it together and it did it again. Simplicity had a recall and replaced them for a 2 year period. Mine was out of warranty so no help. I assume your xmsn is a tuff torq 66L. I replaced my transmisson and have the old one for sale if interested.