Yeah just like Cubey I just put some in to flush out the old junk. I had planned on changing it by now but... I'd planned on having a lot of other stuff done by now too
The best cleaner I’ve ever put in a differential is full synthetic lube. I used Royal Purple in one truck and when I went to buy it for second truck it had almost doubled. I used Walmart tech brand synthetic Instead. As far as I’m concerned it’s Royal Purple without the dye. I’ve been very pleased with it and it cleans the old crud out.