Finished the front & rear diff oil change, as well as the NV5600.
1- Both front and rear diff's on my 2004 Dodge/Cummins 3500 4x4 had high quality, rigid reusable gaskets. After draining/cleaning and reinstalling, I retorgued the bolts to about 30ft/lbs and no leaks. I filled both diff's to 1/4" below filler hole with Amsoil SVG 75w-110 in front and 75w-110 and 75w-140 mixed in the rear.
2-The NV5600 fluid drained out the bottom bolt hole on the PTO cover. I removed both covers to get as much old lube out as possible. Lube looked really nice for 150k miles with no chunks or syncro yellow metal noted. Cleaned the flexmagnet. It had what I consider a rather small amount of very fine metal dust on the magnet for +/- 150k miles. The gears I could see looked perfect. I used gaskets to reinstall the PTO covers, with a little RTV on the top part of the cap screw threads, and refilled with Amsoil synchromesh fluid, about 5 quarts to the bottom of the fill hole (17mm hex). I reinstalled fill plug and added another 1.2 quarts thru the top PTO cover bolt hole and called it good.
Transfer case was changed early Summer with ATF +4 and still looked good.
I'm good for another 100k!
