Hi guys, Whats the final word on synthetic in the differentials? I'm running Lucas 75w90 in my front and rear diff and the guys on the Jeep forum say, conventional is better for the diffs. they say it pulls heat away from the gears better. I'm running the lower viscosity of the two options, and though synthetic would be the best seeing how we see cold winter as well. Any thoughts? The havoline 80w90 is much cheaper than the lucas, Id be happy running it, and just changing it yearly if it was better. The Lucas feels so smooth though, just weather or not it'd run cooler with dino. any thoughts?